Journal articles on the topic 'Ion doped insulators'
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Mizuno, Tomohisa, Kohki Murakawa, Kazuma Yoshimizu, Takashi Aoki, and Toshiyuki Sameshima. "Physical mechanism for photon emissions from group-IV-semiconductor quantum-dots in quartz-glass and thermal-oxide layers." Japanese Journal of Applied Physics 61, SC (February 9, 2022): SC1014. http://dx.doi.org/10.35848/1347-4065/ac3dc9.
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Abstract We experimentally studied the influence of both impurity density and dangling-bond density on PL emissions from group-IV-semiconductor quantum-dots (IV-QDs) of Si and SiC fabricated by hot-ion implantation technique, to improve the PL intensity (I PL) from IV-QDs embedded in two types of insulators of quartz-glass (QZ) with low impurity density and thermal-oxide (OX) layers. First, we verified the I PL reduction in the IV-QDs in QZ. However, we demonstrated the I PL enhancement of IV-QDs in doped QZ, which is attributable to multiple-level emission owing to acceptor and donor ion implantations into QZ. Secondly, we confirmed the large I PL enhancement of IV-QDs in QZ and OX, owing to forming-gas annealing with H2/N2 mixed gas, which are attributable to the reduction of the dangling-bond density in IV-QDs. Consequently, it is possible to improve the I PL of IV-QDs by increasing impurity density and reducing dangling-bond density.
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Dzhumanov, S. "METAL-INSULATOR TRANSITIONS IN DOPED La-BASED SUPER CONDUCTORS WITH SMALL-RADIUS DOPANTS." Eurasian Physical Technical Journal 19, no. 1 (39) (March 28, 2022): 15–19. http://dx.doi.org/10.31489/2022no1/15-19.
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n this work, we study the possibility of realizing two distinct mechanisms of metal-insulator transitions in hole-doped cuprates induced by the localization of charge carriers near the small-radius impurities and in a deformable lattice (i.e. in the absence of impurities). The purpose of this research is to determine the criteria (i.e. conditions) for the existence of the localized states of hole carriers and solve the problem of metal-insulator transitions in La-based cuprates. The advantage of La-based cuprate versus other types of cuprates is that two distinct metal-insulator transitions in La-based cuprates driven by the strong carrier-impurity-phonon and carrier-phonon interactions occur simultaneously in a wider doping range from the lightly doped to heavily doping regime. We show that at very low doping, the separate levels of hole carriers localized near impurities and in a deformable lattice are formed in the charge-transfer gap of the cuprates. As the doping level increases towards underdoped region, the energy levels of such charge carriers start to form energy bands which gradually broaden with increasing doping. We propose a new two-carrier cuprate superconductor model for studying two distinct metal-insulator transitions occurring simultaneouslyin hole-doped La-based cuprate compounds. We demonstrate that when hole carriers reside in impurity and polaron bands, these metal-insulator transitions in La-based superconductors with small-radius dopants occur accordingly in a wide doping range and relatively lower doping levels.
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Liu, Junfang, Die Su, Li Liu, Zhixiao Liu, Su Nie, Yue Zhang, Jing Xia, Huiqiu Deng, and Xianyou Wang. "Boosting the charge transfer of Li2TiSiO5 using nitrogen-doped carbon nanofibers: towards high-rate, long-life lithium-ion batteries." Nanoscale 12, no. 38 (2020): 19702–10. http://dx.doi.org/10.1039/d0nr04618c.
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The nitrogen-doped carbon encapsulated Li2TiSiO5 (the insulator for transferring electrons by first-principles calculation) nanofibers were fabricated. And unexpectedly, it can boost the charge transfer effectively.
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Balin, Katarzyna, Marcin Wojtyniak, Mateusz Weis, Maciej Zubko, Bartosz Wilk, Ruizhe Gu, Pascal Ruello, and Jacek Szade. "Europium Doping Impact on the Properties of MBE Grown Bi2Te3 Thin Film." Materials 13, no. 14 (July 13, 2020): 3111. http://dx.doi.org/10.3390/ma13143111.
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The impact of europium doping on the electronic and structural properties of the topological insulator Bi2Te3 is studied in this paper. The crystallographic structure studied by electron diffraction and transmission microscopy confirms that grown by Molecular Beam Epitaxy (MBE) system film with the Eu content of about 3% has a trigonal structure with relatively large monocrystalline grains. The X-ray photoemission spectroscopy indicates that europium in Bi2Te3 matrix remains divalent and substitutes bismuth in a Bi2Te3 matrix. An exceptional ratio of the photoemission 4d multiplet components in Eu doped film was observed. However, some spatial inhomogeneity at the nanometer scale is revealed. Firstly, local conductivity measurements indicate that the surface conductivity is inhomogeneous and is correlated with a topographic image revealing possible coexistence of conducting surface states with insulating regions. Secondly, Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) depth-profiling also shows partial chemical segregation. Such in-depth inhomogeneity has an impact on the lattice dynamics (phonon lifetime) evaluated by femtosecond spectroscopy. This unprecedented set of experimental investigations provides important insights for optimizing the process of growth of high-quality Eu-doped thin films of a Bi2Te3 topological insulator. Understanding such complex behaviors at the nanoscale level is a necessary step before considering topological insulator thin films as a component of innovative devices.
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Kao, Chyuan-Haur, Chia-Shao Liu, Shih-Ming Chan, Chih-Chen Kuo, Shang-Che Tsai, Ming-Ling Lee, and Hsiang Chen. "Effects of NH3 Plasma and Mg Doping on InGaZnO pH Sensing Membrane." Membranes 11, no. 12 (December 20, 2021): 994. http://dx.doi.org/10.3390/membranes11120994.
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In this study, the effects of magnesium (Mg) doping and Ammonia (NH3) plasma on the pH sensing capabilities of InGaZnO membranes were investigated. Undoped InGaZnO and Mg-doped pH sensing membranes with NH3 plasma were examined with multiple material analyses including X-ray diffraction, X-ray photoelectron spectroscopy, secondary ion mass spectroscopy and transmission electron microscope, and pH sensing behaviors of the membrane in electrolyte-insulator-semiconductors. Results indicate that Mg doping and NH3 plasma treatment could superpositionally enhance crystallization in fine nanostructures, and strengthen chemical bindings. Results indicate these material improvements increased pH sensing capability significantly. Plasma-treated Mg-doped InGaZnO pH sensing membranes show promise for future pH sensing biosensors.
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Widyaiswari, Utami, Budhy Kurniawan, Agung Imaduddin, and Isao Watanabe. "Study of Magnetoresistance Effect and Magnetic Properties of La0.67Sr0.33Mn1-xNixO3 (x = 0 and 0.2) Material Prepared by Sol-Gel Method." Materials Science Forum 966 (August 2019): 363–69. http://dx.doi.org/10.4028/www.scientific.net/msf.966.363.
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Mixed valence manganite materials have been studied due to their interesting physical properties such as their magnetoresistance (MR) effect. The change of Mn3+/Mn4+ ratio affects the possible bonds between anion and cation and their spin structure that may occur in the samples. The aim of this research is to study the change of magnetoresistance effect and magnetic properties of La0.67Sr0.33MnO3 (LSMO) by doping the Mn site with Ni ion. La0.67Sr0.33Mn1-xNixO3 samples were synthesized by using sol-gel method and characterized by using X-ray diffractometer (XRD) and Energy Dispersive X-ray spectroscopy (EDX) to confirm whether Ni has been doped successfully to the parental compound or not. XRD results showed that the samples have a single phase and Ni peak has been detected in the EDX result of Ni-doped LSMO. Resistivity and magnetic measurement showed that LSMO material has ferromagnetic metallic behavior, while x = 0.20 Ni-doped LSMO sample showed paramagnetic insulator behavior. The absolute value of the MR for un-doped sample is higher than the doped sample when the low field is applied, while under the influence of the high magnetic field, it become smaller than the doped sample.
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Reghu, M., Y. Cao, D. Moses, and A. J. Heeger. "Metal-insulator transition in polyaniline doped with surfactant counter-ion." Synthetic Metals 57, no. 2-3 (April 1993): 5020–25. http://dx.doi.org/10.1016/0379-6779(93)90856-r.
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Kasl, C., and M. J. R. Hoch. "The metal–insulator transition in trivalent-ion-doped tungsten bronzes." Journal of Physics: Condensed Matter 26, no. 6 (January 17, 2014): 065601. http://dx.doi.org/10.1088/0953-8984/26/6/065601.
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Lin, Chun, Chyuan Kao, Chan Lin, Kuan Chen, and Yun Lin. "NH3 Plasma-Treated Magnesium Doped Zinc Oxide in Biomedical Sensors with Electrolyte–Insulator–Semiconductor (EIS) Structure for Urea and Glucose Applications." Nanomaterials 10, no. 3 (March 23, 2020): 583. http://dx.doi.org/10.3390/nano10030583.
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This study compared the sensing characteristics of ZnO (ZO) treated with ammonia (NH3) plasma for 1 min, 3 min, and 6 min, under the EIS structure. The measurement results revealed that, after 3 min of NH3 plasma treatment, the Mg-doped ZnO (MZO) sensing film had a high hydrogen ion sensitivity, linearity, hysteresis, and drift rate of 53.82 mV/pH, 99.04%, 2.52 mV, and 1.75 mV/h, respectively. The sensing film was used with sodium and potassium ion solutions, and it performed satisfactorily in sensing hydrogen ions. Additionally, we investigated the biomedical sensing properties of Mg-doped ZnO (MZO) sensing film with regard to urea, creatinine, and glucose solutions and found that the Mg-doped ZnO (MZO) sensing film treated with NH3 plasma for 3 min had the best properties for sensing urea, creatinine, and glucose. Specifically, with glucose, the sensing film achieved the best linearity and sensitivity and of 97.87% and 10.73 mV/mM, respectively. The results revealed that the sensing characteristics varied with the processing environment and are useful in the developing biomedical sensing applications with different sensing elements.
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Qi, Cheng, Yaswanth Rangineni, Gary Goncher, Raj Solanki, Kurt Langworthy, and Jay Jordan. "SiGe Nanowire Field Effect Transistors." Journal of Nanoscience and Nanotechnology 8, no. 1 (January 1, 2008): 457–60. http://dx.doi.org/10.1166/jnn.2008.083.
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Si0.5Ge0.5 nanowires have been utilized to fabricate source-drain channels of p-type field effect transistors (p-FETs). These transistors were fabricated using two methods, focused ion beam (FIB) and electron beam lithography (EBL). The electrical analyses of these devices show field effect transistor characteristics. The boron-doped SiGe p-FETs with a high-k (HfO2) insulator and Pt electrodes, made via FIB produced devices with effective hole mobilities of about 50 cm2V−1s−1. Similar transistors with Ti/Au electrodes made via EBL had effective hole mobilities of about 350 cm2V−1s−1.
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Al-Khalqi, Ensaf Mohammed, Muhammad Azmi Abdul Hamid, Naif H. Al-Hardan, and Lim Kar Keng. "Highly Sensitive Magnesium-Doped ZnO Nanorod pH Sensors Based on Electrolyte–Insulator–Semiconductor (EIS) Sensors." Sensors 21, no. 6 (March 17, 2021): 2110. http://dx.doi.org/10.3390/s21062110.
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For highly sensitive pH sensing, an electrolyte insulator semiconductor (EIS) device, based on ZnO nanorod-sensing membrane layers doped with magnesium, was proposed. ZnO nanorod samples prepared via a hydrothermal process with different Mg molar ratios (0–5%) were characterized to explore the impact of magnesium content on the structural and optical characteristics and sensing performance by X-ray diffraction analysis (XRD), atomic force microscopy (AFM), and photoluminescence (PL). The results indicated that the ZnO nanorods doped with 3% Mg had a high hydrogen ion sensitivity (83.77 mV/pH), linearity (96.06%), hysteresis (3 mV), and drift (0.218 mV/h) due to the improved crystalline quality and the surface hydroxyl group role of ZnO. In addition, the detection characteristics varied with the doping concentration and were suitable for developing biomedical detection applications with different detection elements.
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BASTRUKOV, S. I., I. V. MOLODTSOVA, and PIK-YIN LAI. "OPTICALLY INDUCED ELECTROSTRICTION MODES IN A NANOPARTICLE OF A UNIFORMLY CHARGED ELECTRET." International Journal of Nanoscience 07, no. 06 (December 2008): 291–98. http://dx.doi.org/10.1142/s0219581x08005456.
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The electromagnetic response of a nanoparticle of an ion-doped polymeric elastic insulator, commonly called an electret, is considered in the continuum model of a uniformly charged elastic sphere. The spectral formulae for the frequency of optically induced spheroidal and torsional shear oscillations driven by bulk force of elastic and dielectric stresses are obtained in analytic form. Particular attention is given to the relaxation dielectric mode of the electrostriction response and its stability in the lowest quadrupole mode. The practical usefulness of ultrafine particles of electrets as biolabels capable of accumulating like-charged inclusions uniformly dispersed over the spherical volume of an elastic matrix is briefly discussed.
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Zhao, Jian, Xinzhan Qin, Jiamin Wang, and Manchao He. "Effect of Mg(II) and Na(I) Doping on the Electronic Structure and Mechanical Properties of Kaolinite." Minerals 10, no. 4 (April 20, 2020): 368. http://dx.doi.org/10.3390/min10040368.
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Because kaolinite has multiple defects, it is very important to study the effect of different doped cations on the electronic structure and mechanical properties of kaolinite (Al4Si4O18H8) from the microscopic point of view with the first-principle calculation method. The results exhibited that the doping of Mg(II) and Na(I) makes the ion bond and layer spacing of kaolinite crystal change, and the bond length of the chemical bond between the doped and O atom is positively related to the atomic radius of the doped cations. Compared with undoped kaolinite crystal, the band gap width of the Mg-doped and Na-doped kaolinite crystal was larger, but the typical insulator characteristics were still maintained. Compared with undoped kaolinite crystal, Mg-doped and Na-doped kaolinite crystal had more electron transfer to O, while the Mg–O bond and Na–O bond had more ionic bond properties and less covalent bond composition than the Al–O bond. Finally, the elastic properties of undoped, Mg-doped, and Na-doped kaolinite crystal were further analyzed by calculating the elastic constant matrix. The influence of doping Mg(II) and Na(I) on C11 and C22 was greater than that on C33, indicating that doping had a greater influence on the stiffness in the direction of the parallel crystal plane. The doping of Mg(II) and Na(I) weakened the rigidity of kaolinite crystal materials and improved the plasticity and ductility of the materials. The atom-scale information provided a basis for explaining the mechanical behavior of kaolinite and is expected to provide guidance for solving the deformation problems in soft rock roadways.
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Wang, Yue, Lixin Wang, Yuanzhe Li, Mengyao Cui, and Zhuoxuan Zheng. "A Single-Event Burnout Hardened Super-Junction Trench SOI LDMOS with Additional Hole Leakage Paths." Electronics 11, no. 22 (November 16, 2022): 3764. http://dx.doi.org/10.3390/electronics11223764.
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In this paper, a novel super-junction trench silicon-on-insulator laterally-diffused metal-oxide-semiconductor (SJT SOI LDMOS) power device with additional hole leakage paths to improve single-event burnout (SEB) performance under high liner energy transfer (LET) is proposed for the first time. The electrical characteristics and SEB performance of the proposed SJT SOI LDMOS are both enhanced effectively. The replacement of a lightly doped N drift region with a heavily doped P pillar and N pillar considerably improves the tradeoff between breakdown voltage (BVDS) and specific on-resistance (Ron,sp). Compared with the conventional trench SOI LDMOS (CT SOI LDMOS), the static figures of merit (FOM, BVDS2/Ron,sp) of the SJT SOI LDMOS increases by 239%. The SEB performance of the SJT SOI LDMOS is significantly improved as the holes induced by the heavy ion can be quickly absorbed to the trench source metal through the heavily doped P+ region and P buried region rather than the base resistor of the parasitic bipolar junction transistor (BJT). The SEB threshold voltage (VSEB) of the CT SOI LDMOS is 58 V (39% of the BVDS) and that of the SJT SOI LDMOS is up to 173 V (87% of the BVDS) at high LET of 1 pC/μm.
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ZHANG, JINCANG, YUFENG ZHANG, SHIXUN CAO, and CHAO JING. "EFFECT OF MEAN ION SIZE AND SPATIAL SPIN DISORDERS FOR (La1-xYx)2/3Ca1/3MnO3 MANGANITES." International Journal of Modern Physics B 18, no. 26 (October 30, 2004): 3451–64. http://dx.doi.org/10.1142/s0217979204026615.
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The structure and transport properties of perovskite ( La 1-x Y x)2/3 Ca 1/3 MnO 3 (0≤x≤0.3) systems are systematically investigated. It is found that all the specimens show a single-phase structure and reveal a direct relationship between the Curie temperature Tc and the average ionic radius <rA> of La site. With increasing Y 3+ doped content, the metal-insulator transition temperature T MI (M-I) shifts to lower temperature. While the relevant resistivity peak ρp is sharp increased, for the specimens with large doping content, x=0.3, it has enhanced eight orders of magnitudes larger than the non-doped samples (x=0.0). At high concentration area, that is to say, when x>0.1, magnetic studies show a gradual increase of antiferromagnetic interaction with an increase of x, ultimately leading to a spatial-spin disorders, that is, spin-glass-like state for x=0.2 and x=0.3 compounds at about 35 K. The results show that it has connected a reduction of Tc and an increase in magnetoresistance with a decrease in the microstructural Mn - O - Mn bond angle.
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White, C. W. "Ion Beam Processing." MRS Bulletin 12, no. 2 (March 1987): 18–21. http://dx.doi.org/10.1557/s0883769400068366.
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Ion beams are used extensively in materials research for processing and synthesis as well as for characterization. In the last few years, enormous advances have been made regarding the use of ion beams for processing or synthesis, and this issue of the MRS BULLETIN will review some of those advances. (The use of ion beams for materials characterization will be the subject of a future issue of the BULLETIN.) The areas covered in this issue are ion implantation, ion beam mixing, ion-assisted deposition, and direct ion beam deposition. For each area, recognized experts in the field prepared overview articles that should be very interesting to those who are not active in the field, and that should be useful to other experts in the field.The first large-scale use of ion beams for materials modification took place in the semiconductor industry more than 20 years ago when ion implantation began to be used to dope the near-surface region of silicon with Group III or Group V dopants. The use of ion implantation in the semiconductor industry has undergone explosive growth, and today almost all electronic devices are fabricated utilizing at lest one ion implantation step.In addition to the semiconductor area, research is being carried out using ion implantation in a multitude of other areas which include ceramics, metals and alloys, insulators, etc. The article on “Ion Implantation” by S.T. Picraux and P.S. Peercy provides an excellent overview of current research activities involving ion implantation of a wide spectrum of materials.
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Piatti, Erik, Jessica Montagna Bozzone, and Dario Daghero. "Anomalous Metallic Phase in Molybdenum Disulphide Induced via Gate-Driven Organic Ion Intercalation." Nanomaterials 12, no. 11 (May 27, 2022): 1842. http://dx.doi.org/10.3390/nano12111842.
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Transition metal dichalcogenides exhibit rich phase diagrams dominated by the interplay of superconductivity and charge density waves, which often result in anomalies in the electric transport properties. Here, we employ the ionic gating technique to realize a tunable, non-volatile organic ion intercalation in bulk single crystals of molybdenum disulphide (MoS2). We demonstrate that this gate-driven organic ion intercalation induces a strong electron doping in the system without changing the pristine 2H crystal symmetry and triggers the emergence of a re-entrant insulator-to-metal transition. We show that the gate-induced metallic state exhibits clear anomalies in the temperature dependence of the resistivity with a natural explanation as signatures of the development of a charge-density wave phase which was previously observed in alkali-intercalated MoS2. The relatively large temperature at which the anomalies are observed (∼150 K), combined with the absence of any sign of doping-induced superconductivity down to ∼3 K, suggests that the two phases might be competing with each other to determine the electronic ground state of electron-doped MoS2.
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Wu, Chia-Hsun, Edward Yi Chang, Ping-Cheng Han, Quang Ho Luc, Ching-Yi Hsu, Ting-En Hsieh, Huan-Chung Wang, Yen-Ku Lin, Po-Chun Chang, and Yueh-Chin Lin. "Normally-OFF GaN MIS-HEMT With F− Doped Gate Insulator Using Standard Ion Implantation." IEEE Journal of the Electron Devices Society 6 (2018): 893–99. http://dx.doi.org/10.1109/jeds.2018.2859769.
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Hayashi, Katsuro, Yoshitake Toda, Toshio Kamiya, Masahiro Hirano, Minako Yamanaka, Isao Tanaka, Takahisa Yamamoto, and Hideo Hosono. "Electronic insulator-conductor conversion in hydride ion-doped 12CaO∙7Al2O3 by electron-beam irradiation." Applied Physics Letters 86, no. 2 (January 10, 2005): 022109. http://dx.doi.org/10.1063/1.1852723.
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Dong, Wujie, Tianquan Lin, Jian Huang, Yuan Wang, Zhichao Zhang, Xin Wang, Xiaotao Yuan, Jie Lin, I.-Wei Chen, and Fuqiang Huang. "Electrodes with Electrodeposited Water-excluding Polymer Coating Enable High-Voltage Aqueous Supercapacitors." Research 2020 (October 9, 2020): 1–13. http://dx.doi.org/10.34133/2020/4178179.
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Aqueous supercapacitors are powerful energy sources, but they are limited by energy density that is much lower than lithium-ion batteries. Since raising the voltage beyond the thermodynamic potential for water splitting (1.23 V) can boost the energy density, there has been much effort on water-stabilizing salvation additives such as Li2SO4 that can provide an aqueous electrolyte capable of withstanding ~1.8 V. Guided by the first-principles calculations that reveal water can promote hydrogen and oxygen evolution reactions, here, we pursue a new strategy of covering the electrode with a dense electroplated polymerized polyacrylic acid, which is an electron insulator but a proton conductor and proton reservoir. The combined effect of salvation and coating expands the electrochemical window throughout pH 3 to pH 10 to 2.4 V for both fast and slow proton-mediated redox reactions. This allows activated carbon to quadruple the energy density, a kilogram of nitrogen-doped graphene to provide 127 Watt-hour, and both to have improved endurance because of suppression of water-mediated corrosion. Therefore, aqueous supercapacitors can now achieve energy densities quite comparable to that of a lithium-ion battery, but at 100 times the charging/discharging speed and cycle durability.
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Kao, Chyuan-Haur, Yen-Lin Su, Wei-Jen Liao, Ming-Hsien Li, Wei-Lun Chan, Shang-Che Tsai, and Hsiang Chen. "Effects of CF4 Plasma Treatment on Indium Gallium Oxide and Ti-doped Indium Gallium Oxide Sensing Membranes in Electrolyte–Insulator–Semiconductors." Crystals 10, no. 9 (September 14, 2020): 810. http://dx.doi.org/10.3390/cryst10090810.
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Electrolyte–insulator–semiconductor (EIS) sensors, used in applications such as pH sensing and sodium ion sensing, are the most basic type of ion-sensitive field-effect transistor (ISFET) membranes. Currently, some of the most popular techniques for synthesizing such sensors are chemical vapor deposition, reactive sputtering and sol-gel deposition. However, there are certain limitations on such techniques, such as reliability concerns and isolation problems. In this research, a novel design of an EIS membrane consisting of an optical material of indium gallium oxide (IGO) was demonstrated. Compared with conventional treatment such as annealing, Ti doping and CF4 plasma treatment were incorporated in the fabrication of the film. Because of the effective treatment of doping and plasma treatment, the defects were mitigated and the membrane capacitance was boosted. Therefore, the pH sensitivity can be increased up to 60.8 mV/pH. In addition, the hysteresis voltage can be improved down to 2.1 mV, and the drift voltage can be suppressed to as low as 0.23 mV/h. IGO-based membranes are promising for future high-sensitivity and -stability devices integrated with optical applications.
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Yuehui, Yu, Lin Chenglu, and Zou Shichang. "Optical effects of doped top layers in silicon-on-insulator structures formed by ion implantation." Journal of Materials Science 30, no. 13 (July 1995): 3539–42. http://dx.doi.org/10.1007/bf00349907.
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Park, Jin-Kwon, Jae-Hoon Han, Mitsuru Takenaka, and Shinichi Takagi. "InGaAsP variable optical attenuator with lateral P-I-N junction formed by Ni-InGaAsP and Zn diffusion on III-V on insulator wafer." MRS Advances 1, no. 48 (2016): 3295–300. http://dx.doi.org/10.1557/adv.2016.339.
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ABSTRACTIn this study, we successfully demonstrate a carrier-injection InGaAsP variable optical attenuator (VOA) with a lateral P-I-N junction formed by Ni-InGaAsP alloy and Zn diffusion on a III-V on insulator (III-V-OI) wafer. The Ni-InGaAsP alloy for the n+ junction is formed by direct reaction between Ni and InGaAsP after annealing at 350°C. The p+ junction is formed by the Zn diffusion at 500°C using Zn doped spin-on glass (SOG). By both techniques, we successfully reduce the sheet and contact resistivity in the lateral P-I-N junction even with the relatively low-temperature process as compared with the P-I-N junction formed by conventional Si and Be ion implantation. By injecting carriers into the InGaAsP waveguide through the lateral P-I-N junction, we achieve the optical attenuation of -40 dB/mm with an injection current density of 40 mA/mm at a 1.55 μm wavelength.
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Kawasaki, M., T. Oikawa, K. Ibe, K. H. Park, M. Shiojiri, and M. Kersker. "Compositional Characterization of an O-N-O Layer in a Dram Using FE-TEM and EDS Elemental Mapping." Microscopy and Microanalysis 4, S2 (July 1998): 146–47. http://dx.doi.org/10.1017/s1431927600020857.
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An O-N-O layer within a DRAM is designed to be an insulator between a single-crystal silicon substrate and a poly-crystalline silicon gate. The nominal structure of the layer is SiO2-Si3N4-SiO2. A small amount of phosphorus is doped in the poly-crystalline silicon gate to improve the electrical characteristics of the device. Transmission Electron Microscopy (TEM) was first used to view the micro structure in the layer. A bright field image gave clear contrast in the O-N-O layer, however, TEM images do not provide direct information about the elemental distribution. In this study X-ray elemental mapping was thus used to show this distribution.The specimen was cut from a 16M-DRAM device and thinned using the cross-section ion milling method. The O-N-O layer was examined using a JEM-201 OF FE-(S)TEM equipped with a JEOL UTW-EDS detector. Fig. 1 shows a high resolution TEM image of the O-N-O layer.
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Chrostowski, Marta, José Alvarez, Alessia Le Donne, Simona Binetti, and Pere Roca i Cabarrocas. "Annealing of Boron-Doped Hydrogenated Crystalline Silicon Grown at Low Temperature by PECVD." Materials 12, no. 22 (November 19, 2019): 3795. http://dx.doi.org/10.3390/ma12223795.
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We investigate low-temperature (<200 °C) plasma-enhanced chemical vapor deposition (PECVD) for the formation of p–n junctions. Compared to the standard diffusion or implantation processes, silicon growth at low temperature by PECVD ensures a lower thermal budget and a better control of the doping profile. We previously demonstrated the successful growth of boron-doped epitaxial silicon layers (p+ epi-Si) at 180 °C. In this paper, we study the activation of boron during annealing via dark conductivity measurements of p+ epi-Si layers grown on silicon-on-insulator (SOI) substrates. Secondary Ion Mass Spectroscopy (SIMS) profiles of the samples, carried out to analyze the elemental composition of the p+ epi-Si layers, showed a high concentration of impurities. Finally, we have characterized the p+ epi-Si layers by low-temperature photoluminescence (PL). Results revealed the presence of a broad defect band around 0.9 eV. In addition, we observed an evolution of the PL spectrum of the sample annealed at 200 °C, suggesting that additional defects might appear upon annealing.
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Yang, Fan, Julian S. Dean, Qiaodan Hu, Patrick Wu, Emilio Pradal-Velázquez, Linhao Li, and Derek C. Sinclair. "From insulator to oxide-ion conductor by a synergistic effect from defect chemistry and microstructure: acceptor-doped Bi-excess sodium bismuth titanate Na0.5Bi0.51TiO3.015." Journal of Materials Chemistry A 8, no. 47 (2020): 25120–30. http://dx.doi.org/10.1039/d0ta10071d.
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Wu, Jialiang, Liping Tong, Huifen Wang, Gang Liu, Xuecheng Fu, and Tongxiang Fan. "Regulation of phase transition temperature and preparation for doping-VO2 smart thermal control films." Journal of Applied Physics 131, no. 8 (February 28, 2022): 085101. http://dx.doi.org/10.1063/5.0054066.
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Vanadium dioxide (VO2) is considered one of the most promising smart thermal control materials due to its insulator-metal temperature (IMT) reversible phase transition, accompanied by large changes in its optical properties. However, as the crystal defects on IMT change and the optical property of VO2 is still unclear, the preparation of doped VO2 films by magnetron sputtering is still a great challenge. In this work, the IMT of 41 kinds of doping-VO2 systems were studied by high throughput calculation based on density functional theory (DFT). It was found that the IMT increased with the decrease of the β angle in M phase and expansion of cell volume difference of M-phase and R-phase for IIA elements, VIIA elements, transition elements, and rare earth element doped VO2, and increased with the increase of the β angle in M phase and a decrease of cell volume difference of M-phase and R-phase for IA, IVA, VA, and VIA element doped VO2. According to the rule, the IMT, electronic structures, and optical properties of W doped VO2 were studied based on DFT. The results show that IMT and bandgap decrease with the increase of W6+ ion concentration, which is due to the increased cell volume difference of M-phase and R-phase in W doped VO2; each doped atom can reduce the IMT of 20.2 °C, and the IMT of V0.98W0.02O2 is close to room temperature (Tc ≈ 27 °C). The rate of infrared emissivity (∆ɛ) of V0.98W0.02O2 is about 0.2 at 8–14 μm (0.088–0.155 eV) and the average solar absorption (αs) of M phase and R phase is about 0.53 and 0.59 at 0.3–1.5 μm (0.496–4.13 eV), respectively. Finally, radio frequency magnetron sputtering was used to achieve precise doping, which solved the problem of oxygen partial pressure in reactive magnetron sputtering, and V1-xWxO2 films with IMT close to room temperature and narrow hysteresis width were prepared. This is due to the fact that higher W doping content will greatly increase the density of defect-induced nucleation sites and promote nucleation. At the same time, the experimental results of IMT were consistent with the calculated results, which proved the reliability of the calculation. This will provide a theoretical basis for the development of new thermal control materials and a new method for the preparation of doping-VO2 films in the future.
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Peczek, Anna, Stefan Lischke, Daniel Steckler, Jesse Morgan, Andreas Beling, and Lars Zimmermann. "Versatile Germanium Photodiodes with 3dB Bandwidths from 110 GHz to 265 GHz." ECS Meeting Abstracts MA2022-02, no. 32 (October 9, 2022): 1170. http://dx.doi.org/10.1149/ma2022-02321170mtgabs.
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We demonstrate waveguide coupled germanium fin photodiodes for C- and O-band applications. By scaling the germanium (Ge) fin widths record 3dB-bandwidths reaching from 110GHz to 265GHz are achieved. The intrinsic, undoped germanium fins of the photodiodes are sandwiched in between two complementary in situ-doped silicon regions, circumventing ion-implantation into Ge. This reduces the impact of minority carrier diffusion, which is beneficial for the bandwidth [1,2]. In silicon photonics, waveguide integrated germanium photodiodes are a key asset. However, until 2020 optoelectrical bandwidth of foundry manufactured germanium photodiodes remained substantially below the 100GHz benchmark, typical values ranging up to approximately 70GHz [3,4,5]. All of these devices rely on ion-implantation into silicon and/or germanium. Discrete devices in InP technology, on the other hand, achieved 170GHz bandwidth and 0.27A/W responsivity already several years ago [6]. Having such performance available in silicon technology has been a major motivation for our work. The most recent germanium fin photodiodes show a 3dB-bandwidths of 240GHz (with internal responsivity of 0.45A/W) and 265GHz (with internal responsivity of 0.3A/W) both at 1550nm wavelength and 1mA photocurrent at 2V reverse bias [2]. These devices have been fabricated in IHP’s BiCMOS pilot line on 200mm silicon-on-insulator (SOI) wafers. These novel photodiodes do not rely on ion-implantation, but instead the undoped germanium is contacted by in situ-doped silicon offshoot, thus minimizing minority carrier diffusion effects. This novel technology approach allowed us to match or even surpass the state-of-the-art of III-V devices. By scaling the width of the germanium region, different combinations of bandwidths and responsivities can be realized. Certainly, broader fins will yield higher responsivities but on the expense of 3dB-bandwidths. In this paper, we present for the first time the responsivity and bandwidth at 1310nm and 1550nm, as well as dark current and capacitance of the high-speed germanium fin photodiodes. Several aspects important for high performance photodiodes will be discussed: (1) Optoelectrical 3dB-bandwidths and responsivities for various germanium fin widths. (2) Improved power handling capability of the photodiode at 1310nm and 1550nm. (3) Temperature dependent electrical behaviour for photodiodes with various germanium fin widths. Figure 1 shows STEM cross-sections (cut perpendicular to the light-incidence direction) of the 70GHz Ge photodiode integrated at IHP EPIC platform (left) and a novel germanium-fin photodiode with 3dB-bandwidth of 265GHz (right). Two major changes, the transition from Ge-stripe to germanium fin and from ion-implantation to in situ-doped silicon offshoot, eventually lead to record 3dB-bandwidths. [1] Lischke, S. et al., "Ge photodiode with −3-dB OE bandwidth of 110 GHz for PIC and ePIC platforms", In Proc. 2020 IEEE International Electron Devices Meeting (IEDM) 7.3.1–7.3.4, 2020. [2] Lischke, S., et al., "Ultra-fast germanium photodiode with 3-dB bandwidth of 265 GHz", Nat. Photon. 15, 925–931, 2021. [3] Chen, H., et al., " −1-V bias 67-GHz bandwidth Si-contacted germanium waveguide p-i-n photodetector for optical links at 56 Gbps and beyond", Opt. Express 24, 4622–4631, 2016. [4] Boeuf, F., et al., "A silicon photonics technology for 400-Gbit/s applications", In Proc. 2019 IEEE International Electron Devices Meeting (IEDM) 33.1.1–33.1.4, 2019. [5] Lischke, S., et al., "High bandwidth, high responsivity waveguide-coupled germanium p-i-n photodiode", Optics express, vol. 23, no. 21, pp. 27213–27220, 2015. [6] Rouvalis, E., et al., "170-GHz uni-traveling carrier photodiodes for InP-based photonic integrated circuits", Opt. Express 20, 20090–20095, 2012. Figure 1
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Zawawi, Rabiatul Adawiyah, Nurul Nasuha Khairulzaman, Suhadir Shamsuddin, and Norazila Ibrahim. "Comparative Study on Structural, Electrical Transport and Magnetic Properties of Cr-Doped in Charge-Ordered Pr0.75Na0.25Mn1-Xcrxo3 and Nd0.75Na0.25Mn1-Ycryo3 Manganites." International Journal of Engineering & Technology 7, no. 4.30 (November 30, 2018): 76. http://dx.doi.org/10.14419/ijet.v7i4.30.22016.
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Cr doping in charge-ordered Pr0.75Na0.25Mn1-xCrxO3 and Nd0.75Na0.25Mn1-yCryO3 have been synthesized using conventional solid-state method to investigate its effect on structural, electrical transport and magnetic properties. X-ray diffraction (XRD) analysis for both compounds showed that the samples were crystallized in an orthorhombic structure with Pnma group. The unit cell volume value decrease as the Cr-doped increased indicating the possibility of Mn3+ ion was replaced by Cr3+ due to the different of ionic radius. The temperature dependence of electrical resistivity showed an insulating behavior down to the lower temperature the both parent compound (x = 0 and y = 0). Successive substitution of Cr at Mn-site in Pr0.75Na0.25Mn1-xCrxO3 manganites induced the metal-insulator (MI) transition temperature around TMI~120 K and TMI~122 K for x = 0.02 and x = 0.04 samples respectively suggestively due to the enhancement of double-exchange (DE) mechanism as a result of suppress the CO state. Analysis of resistivity data of dlnρ/dT-1 vs. T in Nd0.75Na0.25Mn1-yCryO3 manganite, showed a peak around 210 K and 160 K for y = 0 and 0.02 samples respectively while no peak was observed for y = 0.05 sample indicate the charge-ordered (CO) weakened. AC susceptibility, χ’ measurements in Pr0.75Na0.25Mn1-xCrxO3 exhibits paramagnetic to ferromagnetic-like with curie temperature, TC increases from 132 K for x = 0.02 to 141 K for x = 0.04 with Cr content indicate the suppression of CO state meanwhile in Nd0.75Na0.25Mn1-yCryO3 showed paramagnetic to anti-ferromagnetic transition as Neel temperature TN increases from 115 K for y = 0.02 to 125 K for y = 0.05.
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Debasis Mukherjee, Rajkumar Mandal,. "Design and Performance Assessment of Split Gate Dielectric Modulated Junction less TFET Variation of Hfo2 by the Divided Gate Insulator for High Sensitivity Using Tcad Simulation." Mathematical Statistician and Engineering Applications 71, no. 4 (December 31, 2022): 9068–81. http://dx.doi.org/10.17762/msea.v71i4.1672.
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A number of more recent discoveries in microbiology have made reliable identification of nano-biomolecules and extensive analyses of them necessary. A variety of proteins, including DNA, biotin-streptavidin, amino acids, as well as many types of bacteria and viruses, must be found and analyzed in order to fully comprehend any odd behavior occurring inside of live cells. Rapid testing and detection are essential steps in preventing undiscovered biohazards from eradicating the human race and other terrestrial living things. Since many decades ago, developing an accurate, affordable biosensor has been a struggle for scientists [1]. When compared to pricey laboratory-based sensors and detection methods, FET-based lab-on-chip nano biosensors appear to be a promising substitute. It is significantly more dependable than conventional bulk sensors because of its size, affordability, low power consumption, resilience, faster response time, and better sensitivity [1]. Due to their precision, adaptability, and compatibility with embedded systems, dielectrically modulated FET biosensors with Nano cavities are emerging as a promising research area that can yield useful data on bio-analyses. As an alternative to conventionally doped TFET devices, using a charge plasma SiGe-heterojunction double gate TFET, a label-free biosensor can be produced, bypassing the need for conventional semiconductors, which require a large thermal budget and are susceptible to random dopant fluctuations (RDFs). The effect of changing the dielectric constant (k), the positive and negative charge density, the gate work function, and the cavity size has been investigated to better understand how these factors affect the performance of the proposed biosensor. These parameters modify the biosensor's electric characteristics, improving detection [2]. There is also discussion of how these factors influence the device's drain current, electric field, surface potential, sub-threshold swing (SS), insulator-to-metal film (ION/IOFF) ratio, and electron tunneling rate (ETR). The sensitivity of the drain current in the proposed biosensor is also investigated. There is no restriction on whether or whether the proposed structure is used for charged or neutral molecules.Under lower supply voltages, it is discovered that the SG-DM current JLFET's sensitivity is high, measuring 1.2 *10^3, with a potential sensitivity of 1.4 V. A result, the SG-DM [2] JLFET exhibits good application potential while consuming little power and having ahigh sensitivity.
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Sanjay, Sooraj, Fahimul Islam Sakib, Mainul Hossain, and Navakanta Bhat. "(Invited, Digital Presentation) Super-Nernstian Isfet Combining Two-Dimensional WSe2/MoS2 Heterostructure with Negative Capacitance." ECS Meeting Abstracts MA2022-02, no. 15 (October 9, 2022): 823. http://dx.doi.org/10.1149/ma2022-0215823mtgabs.
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Ion-sensitive field-effect transistors (ISFETs) are quite popular as compact, low-cost biosensors with fast response time and label-free detection1. They can be used as pH sensors or functionalized for complex biomolecule detection. The voltage sensitivity (Sv) in classical ISFETs is fundamentally limited to 59 mV/pH (Nernst limit). Surpassing the Nernst limit requires complex device architectures or novel transport phenomena. Sensitivity beyond the Nernst limit can be achieved using specific device architectures such as dual gate ISFETs2, negative capacitance ISFETs (NC-ISFET)3, tunnel ISFETs4, etc. Compatible architectures can be combined for further enhancements in sensitivity. First, we experimentally demonstrate a super-Nernstian hetero-ISFET that uses 2-D WSe2/MoS2 heterostructure in a double-gated configuration5. The schematic of the device structure is shown in Fig. 1(a) along with its dimensions. The fluid gate to the pH solution is biased at VFG = 0 V and the voltage sensitivity (SV) is extracted by applying bias to the back-gate (VBG). Fig. 1(b) shows the variation of drain current for change in VBG at different pH. The voltage sensitivity is also included in the same graph. The device uses charge screening due to the interface traps and inversion charges at the hetero-interface to modulate the back-gate transconductance (gmb), thereby allowing super sensitivity. Further enhancement in sensitivity is explored using technology computer-aided (TCAD) device simulator tool (Silvaco ATLAS) by integrating with different device architectures. First we model the baseline hetero-ISFET. The 2-D materials were modeled using their material parameters and 3-D equivalents of their density of states. Amorphous hafnium oxide (HfO2) was used as the dielectric. The mobile ions in the electrolyte were modeled as charge carriers in an intrinsic semiconductor, with its effective density of states varying as a function of pH. The simulation model was calibrated with the experimental device (at pH = 7), as shown in Fig. 2(a). The transfer characteristics of the back-gate at different pH and fixed VFG (= 0 V) for the simulated device is shown in Fig. 2(b). We note that the sensitivity from simulations is lower than the experimental device. This is likely due to non-ideal and 2-D material specific factors which are not accounted in simulations. Nevertheless, the simulated device also shows super-Nernstian sensitivity (Fig. 2(b), right axis), validating the model. Hence, the calibrated TCAD model is used as the baseline for further studies. Next, an NC-FE layer (aluminum-doped HfO2) was added to the top fluid-gate stack6. We have used a ferroelectric-metal-insulator-semiconductor (FMIS) stack for the proposed NC-hetero-ISFET. Fig. 3(a) shows the new top-gate stack with the FMI layer, which replaces the top-gate stack in the earlier schematic. The fluid-gate charge (QFG), and drain current (ID) as a function of VFG (VBG = 0 V), were obtained from the TCAD simulations. The 1-D Landau–Khalatnikov (L-K) equations were used to model the voltage across the FE layer (VFE = 2αQFG+4βQ3 FG = V' FG - Vint; where V' FG is the newly computed fluid-gate bias and Vint is the internal node voltage)7. The calculated Vint (for fixed V' FG) is coupled back into the ATLAS simulator to extract voltage sensitivity (SV) by sweeping VBG at different pH values. The fluid-gate transfer curve of the proposed NC-hetero-ISFET, in Fig. 3(b), clearly shows a steeper sub-threshold slope and higher ON current than the baseline device. The corresponding FE layer parameters are shown in Table 1. These improved fluid-gate characteristics contribute to an increased voltage-sensitivity (SV) when VBG is applied. The transfer characteristic (ID v/s VBG, at fixed V' FG) of the NC-hetero-ISFET at different pH values is shown in Fig. 3(c), along with the voltage sensitivity. Further, in Fig. 3(d), we compare the peak SV obtained at different V' FG. There is an improvement in voltage sensitivity (as much as ~ 100 mV/pH) over the baseline device when NC is introduced. The results pave the way for highly sensitive super-Nernstian ISFETs by combining 2-D heterostructure with NC effect. References: P. Bergveld, Sensors Actuators, B Chem., 88, 1–20 (2003). M. Spijkman et al., Appl. Phys. Lett., 98, 2011–2014 (2011). F. Bellando et al., Appl. Phys. Lett., 116, 173503 (2020) P. Dwivedi, R. Singh, and Y. S. Chauhan, IEEE Sens. J., 21, 3233–3240 (2021). S. Sanjay, M. Hossain, A. Rao, and N. Bhat, npj 2D Mater. Appl. 2021 51, 5, 1–8 (2021) S. Salahuddin and S. Datta, Nano Lett, 8, 405–410 (2008) F. I. Sakib, M. A. Hasan, and M. Hossain, IEEE Trans. Electron Devices, 69, 311–317 (2022). Figure 1
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Lui, M., R. A. Mcfarlane, and D. Yap. "Mbe Growth of Rare-Earth Doped Fluoride Insulators on Semiconductors for Laser Applications." MRS Proceedings 301 (1993). http://dx.doi.org/10.1557/proc-301-331.
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ABSTRACTWith the recent success of using rare-earth doped fluoride crystals as high power visible upconversion lasers, we have explored the use of MBE grown fluoride layers for a possible waveguide laser. By confining the pumped light in a waveguide with dimensions on the order of a few micron, the pump power density will increase promoting higher efficiencies at room temperatures. Initially, we have grown planar waveguides of erbium doped ZnF2 on MgF2 substrates using molecular beam epitaxy and have formed channel waveguides by ion milling. By exciting individual channels with an 800 nm pump, we have generated strong upconversion fluorescence at 410 nm, 550 nm and 670 nm and at numerous weaker peaks. The fabrication techniques can be adapted to semiconductor substrates for making compact diode-pumped visible and infrared lasers. A number of fluoride materials that are useful as laser host crystals are lattice matched to GaAs (100) and GaAs (111) offering the possibility of integrating the channel waveguide laser with the semiconductor diode laser pump source. For example SrF2 may be grown on GaAs (100) as a cladding layer followed by PbF2 doped with a rare-earth ion. Also LaF3 may be grown on GaAs (111) followed by CeF3 doped with a rare-earth ion. Both PbF2 and CeF3 have low phonon energies and a higher index of refraction than their respective lattice matched cladding layers and should be capable of provide an attractive upconversion laser waveguide system. Our initial upconversion luminescence results on erbium doped PbF2 on GaAs (100) using a intervening SrF2 cladding layer are also reported.
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Yamamoto, Hideki, Osamu Matsumoto, Keitaro Yamagami, Michio Naito, and Yoshiharu Krockenberger. "Superconducting Parent Compound Pr2CuO4 Achieved by Special Post-Reduction." MRS Proceedings 1309 (2011). http://dx.doi.org/10.1557/opl.2011.97.
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ABSTRACTIt is commonly believed that the parent compounds of high-Tc cupratres are, universally, charge transfer insulators and triggered by Mott physics. In our experiments using metal-organic decomposition (MOD), however, accumulating evidences show that the parent compounds of “electron-doped” superconductors, RE2-xCexCuO4 [RE = rare earth ion] with x = 0, are not Mott insulators but superconductors [1-5]. They have a Tc of 30 K and crystallize in the Nd2CuO4 (T’) structure. Most likely, the sharp contradiction between our results and commonly achieved data originates from the complicated oxygen chemistry in these materials. The as-synthesized specimens contain a fair amount of impurity interstitial oxygen. Throughout the reduction process it is required to remove exclusively impurity oxygen while preserving regular oxygen site occupied in order to obtain superconductivity. With decreasing x the constraints of the reduction process are getting more tight. In this study, we systematically investigated the post-annealing process using MBE-grown T’-Pr2CuO4 films. The MBE films were reduced ex-situ in a tubular furnace following a specially designed 2-step process, as in the case of MOD films. The films were annealed at Ta = 700 - 850°C in a reducing atmosphere (PO2 = 2 x 10−5 − 2 x 10−3 atm) and finally reduced at a lower temperature Tred = 450 – 700°C under vacuum (< 10−4 Torr). The film properties systematically changed with Ta, PO2, and Tred. The optimized Tred varies from 475°C to 650°C mainly depending on Ta, since the microstructure and grain size of the films are determined by Ta. Optimal superconducting properties are Tc of 26 K, while ρ(300 K) = 250 μΩcm, and RRR ~ 10. We believe the combination of thin-film synthesis and specially designed post-reduction process enabled us to obtain nearly intact CuO2 planes. Samples prepared by above-mentioned method unveiled the intrinsic properties of the parent compounds, which are not triggered by Mott physics. This result also agrees with the recent calculation result indicating the parent compounds with T’ structure are not charge transfer insulators [6-8].
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Kong, H., H. J. Kim, J. A. Edmond, J. W. Palmour, J. Ryu, C. H. Carter, J. T. Glass, and R. F. Davis. "Growth, Doping, Device Development and Characterization of CVD Beta-SiC Epilayers on Si(100) and Alpha-SiC(0001)." MRS Proceedings 97 (1987). http://dx.doi.org/10.1557/proc-97-233.
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ABSTRACTMonocrystalline β-SiC films have been chemically vapor deposited on Si(100) and c-SiC(0001) at 1660K-1823K and 0.1 MPa using SiH4 and C2H4 carried in H2. Films grown directly on Si(100) contained substantial concentrations of dislocations, stacking faults and antiphase boundaries (APB); those on α-SiC(0001) contained double positioning boundaries. Both the APBs and the double positioning boundaries were eliminated by using off-axis orientations of the respective substrates. Films produced on Si(100) have also been doped during growth and via ion implantation with B or Al (p-type) or P or N (n-type) at LN, room and elevated temperatures. Results from the former procedure showed the ionized dopant/total dopant concentration ratios for N, P, B and Al to be 0.1, 0.2, 0.002 and 0.01, respectively. The solubility limits of N, P and B at 1660K were determined to be ∼ 2E20, 1E18 and 8E18 cm−3, respectively; that of Al exceeds 2E19 cm−3. High temperature ion implantation coupled with dynamic and post annealing resulted in a markedly reduced defect concentration relative to that observed in similar research at the lower temperatures. Schottky diodes, p-n junctions, and MOSFET devices have been fabricated. The p-n junctions have the characteristics of insulators containing free carriers and deep level traps. The MOSFETs show very good I-V characteristics up to 673K, but have not been optimized.
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McFadden, Ryan M. L., Aris Chatzichristos, David L. Cortie, Derek Fujimoto, Yew San Hor, Huiwen Ji, Victoria L. Karner, et al. "Local electronic and magnetic properties of the doped topological insulators Bi2Se3:Ca and Bi2Te3:Mn investigated using ion-implanted 8Li β−NMR." Physical Review B 102, no. 23 (December 28, 2020). http://dx.doi.org/10.1103/physrevb.102.235206.
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Aleshin, Andrej N., Nikita B. Mironkov, Alexander V. Suvorov, Jeanine A. Conklint, Timothy M. Su, and Richard B. Kaner. "Electrical Properties of Ion Implanted and Chemically Doped Polyaniline Films." MRS Proceedings 413 (1995). http://dx.doi.org/10.1557/proc-413-609.
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ABSTRACTThe electronic transport mechanism for ion implanted and chemically doped polyanilinefilms was investigated through temperature dependent dc conductivity measurements over thetemperature range 1.8 – 300K. Chemically synthesized emeraldine base polyaniline free-standingfilms (∼40 µm thick) were irradiated by Ar ions at an energy of 90 keV and doses ranging from 1 ×1014 to 3 × 1017 cm-2 to an estimated thickness of 100 nm. Chemical modification of Polyanilinefilms consisted of doping with 1.0 M H2SO4.Ion implantation and chemical doping were found to considerably increase the roomtemperature dc conductivity of polyaniline films reaching values up to 800 S cm-1and 8 S cm-1, respectively. Both ion irradiated and chemically doped polyaniline films exhibit p-type conduction.An increase in the irradiation dose increases the stability of the conducting layer compared tochemical doping. In both cases the samples are on the insulator side of the metal-insulatortransition, where cr(T) exhibits a common temperature dependent characteristic of the variablerange hopping (VRH) transport mechanism:σ(T) = σ (0) exp[ - (To / T)m ] (1)where m = 0.5 and To = 103 to 104K. The influence of electron-electron Coulomb the low temperature VRH of ion implanted and chemically doped polyanilCinoeu floilmmbs iisn tperreascetniotend
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Kwon, C., Q. X. Jia, Y. Fan, M. F. Hundley, D. W. Reagor, M. E. Hawley, and D. E. Peterson. "Observation of Large Low Field Magnetoresistance in Ramp-Edge Tunneling Junctions Based on Doped Manganite Ferromagnetic Electrodes and A SrTiO3 Insulator." MRS Proceedings 494 (1997). http://dx.doi.org/10.1557/proc-494-237.
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ABSTRACTWe report the fabrication of ferromagnet-insulator-ferromagnet junction devices using a ramp-edge geometry based on (La0.7Sr0.3)MnO3 ferromagnetic electrodes and a SrTiO3 insulator. The multilayer thin films were deposited using pulsed laser deposition and the devices were patterned using photolithography and ion milling. As expected from the spin-dependent tunneling, the junction magnetoresistance depends on the relative orientation of the magnetization in the electrodes. The maximum junction magnetoresistance (JMR) of 30 % is observed below 300 Oe at low temperatures (T < 100 K).
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Kasama, Yasuhiko, Tadahiro Ohmi, Koich Fukuda, Hirobumi Fukui, Chisato Iwasaki, and Shoich Ono. "Improvement Of Pecvd-SiNx For Tft Gate Insulator By Controlling Ion Bomberdment Energy." MRS Proceedings 415 (1995). http://dx.doi.org/10.1557/proc-415-57.
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ABSTRACTIt has been revealed that ion energy and ion flux density play an essentially critical role in SiNx deposition process of PECVD in TFT-LCD production. Ion energy and ion flux density bombarding onto substrate surface are known to be extracted from waveform of RF applied to an electrode. Using this method, authors investigated film quality of SiNx formed in the conventional parallel plate PECVD equipment. When N2+H2 or N2+Ar is employed as a carrier gas in source gas(SiH4+NH3), authors have defined normalized ion flux density as ion flux density divided by deposited SiNx molecule which must be increased to obtain high quality SiNx film while ion energy is suppressed at low level as not giving damages on the film surface. This technique has made it possible to securely form SiNx film (2500 Å) featuring dielectric breakdown field intensity of 8.5MV/cm at 250°C on a glass substrate with Cr gate interconnects of 1000 Å having vertical step structure. One of the important factors to improve film quality of SiNx deposited in PECVD is to increase ion flux density while keeping ion energy low enough to protect growing surface against any damages. Using this technique inverse-staggered TFT-array featuring field effect mobility of 0.96 •/V·s has been demonstrated which gate insulator SiNx, non-doped a-Si:H and a- Si:H(n+) were formed continuously at the same substrate temperature of 2500°C.
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Fang, Mei, Wolfgang Voit, Adrica Kyndiah, Yan Wu, Lyubov Belova, and K. V. Rao. "Room temperature ferromagnetism of Fe-doped ZnO and MgO thin films prepared by ink-jet printing." MRS Proceedings 1394 (2012). http://dx.doi.org/10.1557/opl.2012.824.
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ABSTRACTRoom temperature magnetic properties of un-doped, as well as 10 at.% Fe-doped ZnO and MgO single-pass layer of ink-jet printed thin films have been investigated to obtain insight into the role of the band gaps and mechanisms for the origin of ferromagnetic order in these materials. It is found that on doping with Fe, the saturation magnetization is enhanced by several-fold in both systems when compared with the respective un-doped thin films. For a “28 nm thick film of Fe-doped ZnO (Diluted Magnetic Semiconductor, DMS) we observe an enhanced moment of 0.465μB /Fe atom while it is around 0.111μB/Fe atom for the doped MgO (Diluted Magnetic Insulator, DMI) film of comparable thickness. Also, the pure ZnO is far more ferromagnetic than pure MgO at comparable low film thicknesses which can be attributed to defect induced magnetism originating from cat-ion vacancies. However, the film thickness dependence of the magnetization and the defect concentrations are found to be significantly different in the two systems so that a comparison of the magnetism becomes more complex for thicker films.
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Wirbeleit, Frank, Volker Grimm, Christian Krüger, Christoph Streck, Roger Sonnemans, and Ivan Berry. "USJ Dopant Bleaching and Device Effects in Advanced Microelectronic Plasma Enhanced Resist Strip Processing." MRS Proceedings 1070 (2008). http://dx.doi.org/10.1557/proc-1070-e01-12.
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ABSTRACTThe impact of low temperature plasma resist strip on doped silicon surface and microelectronic device performance is investigated using different chemical gas mixtures. In this investigation, different plasma treatments where applied on non-structured and structured silicon on insulator (SOI) wafers post ultra shallow surface implants .The main surface impacts dopant bleaching and oxide loss in conjunction with plasma enhanced re-oxidation are analyzed by time of flight secondary ion mass spectrometry (TOF-SIMS) and electrical measurements of microelectronic test devices. As the result, a long range plasma radiation induced dopant activation and deactivation is separated as the main effect from surface oxide loss and re-oxidation processes. This implies further optimization of plasma resist strip processes for device improvements.
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Cross, Michael, and Walter Varhue. "Visible Light Emission from Erbium Doped Yttria Stabilized Zirconia." MRS Proceedings 789 (2003). http://dx.doi.org/10.1557/proc-789-n11.8.
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ABSTRACT: One of the major shortcomings of silicon (Si) as a semiconductor material is its inability to yield efficient light emission. There has been a continued interest in adding rare earth ion impurities such as erbium (Er) to the Si lattice to act as light emitting centers. The low band gap of Si however has complicated this practice by quenching and absorbing this possible emission. Increasing the band gap of the host has been successfully tried in the case of gallium nitride (GaN) [1] and Si-rich oxide (SRO) [2] alloys. A similar approach has been tried here, where Er oxide (ErOx) nanocrystals have been formed in a yttria stabilized zirconia (YSZ) host deposited on a Si (100) substrate. The YSZ is deposited as a heteroepitaxial, insulating layer on the Si substrate by a reactive sputtering technique. The Er is also incorporated by a sputtering process from a metallic target and its placement in the YSZ host can be easily controlled. The device structure formed is a simple metal contact/insulator/phosphor sandwich. The device has been found to emit visible green light at low bias voltages. The advantage of this material is that it is much more structured than SiO2 which can theoretically lead to higher emission intensity.
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Li, Xiaojing, Wen Yang, Liangzhong Lin, and Zhenhua Wu. "Electric field tuning of spin splitting in topological insulator quantum dots doped with a single magnetic ion." Scientific Reports 9, no. 1 (June 24, 2019). http://dx.doi.org/10.1038/s41598-019-45067-5.
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Holmes, Stuart Nicholas, J. Gough, Chong Chen, David A. Ritchie, and Michael Pepper. "Variable Range Hopping Conductivity in Molecular Beam Epitaxial InSb." Journal of Physics D: Applied Physics, September 22, 2022. http://dx.doi.org/10.1088/1361-6463/ac941c.
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Abstract A Variable Range Hopping-VRH transport mechanism can be induced in molecular beam epitaxial, n-type doped InSb wafers with focussed Ga+ ion beam damage. This technique allows areas of wafer to be selectively damaged and then subsequently processed into gated MISmetal-insulator-semiconductor devices where a disordered, two-dimensional device can be established. At high levels of damage (dose > 1016 Ga+ ions/cm2) amorphous crystalline behaviour results with activated conductivity characteristic of a three-dimensional system with VRH below 150 K. At lower doses (1014 to 1016 Ga+ ions/cm2) a thermally activated conductivity is induced at ~ 0.9 K, characteristic of Mott phonon-assisted VRH. At 1 K the devices either conduct with conductivity > ~ (e2/h) where e is the fundamental charge and h is Planck’s constant, or are thermally activated depending on the dose level. The lightly damaged devices show weak antilocalization signals with conductivity characteristic of a two-dimensional electronic system. As the Ga+ dose increases, the measured phase coherence length reduces from ~ 500 nm to ~ 100 nm. This provides a region of VRH transport where phase-coherent transport processes can be studied in the hopping regime with the dimensionality controlled by a gate voltage in an MIS-device.
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Shinn, N. D., M. E. Bartram, J. E. Schirber, D. L. Overmyer, J. W. Rogers, Z. Fisk, and S. W. Cheong. "Thermal Desorption Studies of Isotopically-Labeled Oxygen from La2Cuo4+δ." MRS Proceedings 209 (1990). http://dx.doi.org/10.1557/proc-209-825.
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ABSTRACTIsotopically-labeled oxygen enrichment and thermal desorption mass spectroscopy (TDMS) have been combined to study interstitial oxygen desorption from superconducting La2CuO4+δ(δ≤5 0.032). Single crystal samples of magnetic, insulating La2CuO4+δ were annealed at 860K under 1-3 kbar oxygen pressure for 12-100 hours to yield hole-doped, superconducting La2CuO4+δ samples with 35K <Tc <40K. Whereas no TDMS signals were observed for the insulator, rapid bursts (FWHM <0.5 sec) of molecular oxygen were observed above 350K while heating the superconductor at less than I K sec−1 in high vacuum. A kinetic model is proposed in which the interstitial oxygen diffuses to internal grain boundaries and defects during heating, thereby inducing stress in the lattice as it attempts to revert to the LaCuO4.00 crystal structure. This stress is relieved by lattice fracture at grain boundaries during the TDMS experiment, releasing the trapped oxygen from the sample as micro-cracks are formed. In addition, the facile oxygen exchange between interstitial and latticeoxygen sites has been discovered by TDMS and weight gain measurements from isotopically-enriched crystals, supporting thestructural model of Chaillout, et al. in which the interstitial oxygen atom dimerizes with a lattice oxygen ion.
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Borenstein, J. T., N. D. Gerrish, R. White, M. T. Currie, and E. A. Fitzgerald. "Silicon Germanium Epitaxy: A New Material for MEMS." MRS Proceedings 657 (2000). http://dx.doi.org/10.1557/proc-657-ee7.4.
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ABSTRACTA wide array of materials have been investigated as candidate fabrication templates for precision microelectromechanical structures, including boron-diffused silicon, boron-doped epitaxial silicon, polysilicon, silicon-on-insulator, and wafer-thick bulk structures. Here we present the latest fabrication results for epitaxial silicon-germanium alloys, a new class of materials which possess excellent crystalline structure, are compatible with non-toxic etchants in bulk micromachining, and are capable of on-chip integration with electronics. For MEMS applications, silicon-germanium alloy layers are grown using a graded buffer approach, resulting in very high quality micromachined structures. Very low defect densities are obtained through the use of these relaxed buffers. Original etch-stop studies determined that Ge doping provided a very weak selectivity in anisotropic etchants such as KOH and EDP. However, by extending the range of Ge concentration to over 20%, we have found extremely high etch selectivities in a variety of etchants. Unlike boron-doped layers, SiGe exhibits etch stop characteristics in the non-toxic, process compatible solution TMAH. The combination of independence from boron doping concentration and etchant compatibility make SiGe a material which is ideal for integration with on-chip electronics.In this work we present the latest fabrication data on comb-drive resonators built using SiGe epitaxial layers. Process compatibility issues related to wafer curvature, surface finish and reactive-ion-etching chemistries are addressed. An unexpected result of the fabrication process, curvature of released structures, is resolved by annealing wafers after the SiGe deposition. Changes in Young's modulus arising from the high atomic fraction of Ge in the device can be determined by simple beam analysis based on observed resonant frequencies. Overall, build precision for these devices is excellent. We conclude by addressing the remaining challenges for wide-scale implementation of silicon-germanium epitaxial MEMS.
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Nazir, Safdar. "Insulator-to-half metal transition and enhancement of structural distortions in $$\text {Lu}_2 \text {NiIrO}_6$$ double perovskite oxide via hole-doping." Scientific Reports 11, no. 1 (January 13, 2021). http://dx.doi.org/10.1038/s41598-020-80265-6.
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AbstractUsing density functional theory calculations, we found that recently high-pressure synthesized double perovskite oxide $$\text {Lu}_2 \text {NiIrO}_6$$ Lu 2 NiIrO 6 exhibits ferrimagnetic (FiM) Mott-insulating state having an energy band gap of 0.20 eV which confirms the experimental observations (Feng et al. in Inorg Chem 58:397–404, 2019). Strong antiferromagnetic superexchange interactions between high-energy half-filled $$\text {Ni}^{+2}$$ Ni + 2 -$$e_g^2\uparrow$$ e g 2 ↑ and low-energy partially filled $$\text {Ir}^{+4}\,t_{2g}^3\uparrow t_{2g}^2\downarrow$$ Ir + 4 t 2 g 3 ↑ t 2 g 2 ↓ orbitals, results in a FiM spin ordering. Besides, the effect of 3d transition metal (TM = Cr, Mn, and Fe) doping with 50% concentration at Ni sites on its electronic and magnetic properties is explored. It is established that smaller size cation-doping at the B site enhances the structural distortion, which further gives strength to the FiM ordering temperature. Interestingly, our results revealed that all TM-doped structures exhibit an electronic transition from Mott-insulating to a half-metallic state with effective integral spin moments. The admixture of Ir 5d orbitals in the spin-majority channel are mainly responsible for conductivity, while the spin minority channel remains an insulator. Surprisingly, a substantial reduction and enhancement of spin moment are found on non-equivalent Ir and oxygen ions, respectively. This leads the Ir ion in a mixed-valence state of $$+4$$ + 4 and $$+5$$ + 5 in all doped systems having configurations of $$5d^5$$ 5 d 5 ($$t_{2g}^3\uparrow t_{2g}^2\downarrow$$ t 2 g 3 ↑ t 2 g 2 ↓ ) and $$5d^4$$ 5 d 4 ($$t_{2g}^2\uparrow t_{2g}^2\downarrow$$ t 2 g 2 ↑ t 2 g 2 ↓ ), respectively. Hence, the present work proposes that doping engineering with suitable impurity elements could be an effective way to tailor the physical properties of the materials for their technological potential utilization in advanced spin devices.
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Abidin, Wan Amirah Basyarah Zainol, Mohammad Nuzaihan Md Nor, Mohd Khairuddin Md Arshad, Mohamad Faris Mohamad Fathil, Nor Azizah Parmin, Noor Azrina Haji Talik Sisin, Conlathan Ibau, and Aidil Shazereen Azlan. "Femtomolar Dengue Virus Type-2 DNA Detection in Back-gated Silicon Nanowire Field-effect Transistor Biosensor." Current Nanoscience 17 (February 26, 2021). http://dx.doi.org/10.2174/1573413717666210226120940.
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Background: Dengue is known as the most severe arboviral infection in the world that spread by Aedes aegypti. However, conventional and laboratory-based enzyme-linked immunosorbent assays (ELISA) are the present approached in detecting dengue virus (DENV), required skilled and well-trained personnel to operate. Therefore, the ultrasensitive and label-free technique of Silicon Nanowire (SiNW) biosensor was chosen for rapid detection of DENV. Methods: In this study, a SiNW field-effect transistor (FET) biosensor integrated with a back-gate of the low-doped p-type Silicon-on-insulator (SOI) wafer was fabricated through conventional photolithography and Inductively Coupled Plasma – Reactive Ion Etching (ICP-RIE) for Dengue Virus type-2 (DENV-2) DNA detection. The morphological characteristics of back-gated SiNW-FET were examined using a field-emission scanning electron microscope supported by the elemental analysis via energy-dispersive X-ray spectroscopy. Results and Discussion: A complementary (target) single-stranded s deoxyribonucleic acid (ssDNA) was recognized when the target DNA was hybridized with the probe DNA attached to SiNW surfaces. Based on the slope of the linear regression curve, the back-gated SiNW-FET biosensor demonstrated the sensitivity of 3.3 nAM-1 with a detection limit of 10 fM. Furthermore, the drain and back-gate voltages were also found to influence the SiNW conductance changed. Conclusion: Thus, the results obtained suggest that the back-gated SiNW-FET shows good stability in both biosensing applications and medical diagnosis throughout conventional photolithography method.