Artykuły w czasopismach: „Undoped Semiconductors”

1

Yang, Jin-Peng, Hai-Tao Chen i Gong-Bin Tang. "Modeling of thickness-dependent energy level alignment at organic and inorganic semiconductor interfaces". Journal of Applied Physics 131, nr 24 (28.06.2022): 245501. http://dx.doi.org/10.1063/5.0096697.

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We identify a universality in the Fermi level change of Van der Waals interacting semiconductor interfaces. We show that the disappearing of quasi-Fermi level pinning at a certain thickness of semiconductor films for both intrinsic (undoped) and extrinsic (doped) semiconductors over a wide range of bulk systems including inorganic, organic, and even organic–inorganic hybridized semiconductors. The Fermi level ( EF) position located in the energy bandgap was dominated by not only the substrate work function (Φsub) but also the thickness of semiconductor films, in which the final EF shall be located at the position reflecting the thermal equilibrium of semiconductors themselves. Such universalities originate from the charge transfer between the substrate and semiconductor films after solving one-dimensional Poisson's equation. Our calculation resolves some of the conflicting results from experimental results determined by using ultraviolet photoelectron spectroscopy (UPS) and unifies the general rule on extracting EF positions in energy bandgaps from (i) inorganic semiconductors to organic semiconductors and (ii) intrinsic (undoped) to extrinsic (doped) semiconductors. Our findings shall provide a simple analytical scaling for obtaining the “quantitative energy diagram” in the real devices, thus paving the way for a fundamental understanding of interface physics and designing functional devices.

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Fortunato, Elvira, Alexandra Gonçalves, António Marques, Ana Pimentel, Pedro Barquinha, Hugo Águas, Luís Pereira i in. "Multifunctional Thin Film Zinc Oxide Semiconductors: Application to Electronic Devices". Materials Science Forum 514-516 (maj 2006): 3–7. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.3.

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In this paper we report some of the recent advances in transparent thin film oxide semiconductors, specifically zinc oxide (ZnO), produced by rf magnetron sputtering at room temperature with multifunctional properties. By controlling the deposition parameters it is possible to produce undoped material with electronic semiconductor properties or by doping it to get either n-type or p-type semiconductor behavior. In this work we refer our experience in producing n-type doping ZnO as transparent electrode to be used in optoelectronic applications such as solar cells and position sensitive detectors while the undoped ZnO can be used as UV photodetector or ozone gas sensor or even as active layer of fully transparent thin film transistors.

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Ma, Yandong, Ying Dai i Baibiao Huang. "ChemInform Abstract: Ferromagnetism in Undoped Semiconductors". ChemInform 42, nr 42 (27.09.2011): no. http://dx.doi.org/10.1002/chin.201142213.

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Sacco, Olga, Antonietta Mancuso, Vincenzo Venditto, Stefania Pragliola i Vincenzo Vaiano. "Behavior of N-doped TiO2 and N-doped ZnO in Photocatalytic Azo Dye Degradation under UV and Visible Light Irradiation: A Preliminary Investigation". Catalysts 12, nr 10 (10.10.2022): 1208. http://dx.doi.org/10.3390/catal12101208.

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N-doped TiO2 (N-TiO2) and N-doped ZnO (N-ZnO) were synthesized utilizing ammonia as a dopant source. The chemico-physical characteristics of synthesized samples were studied by Raman spectroscopy, X-ray diffraction, SEM analysis, N2 adsorption–desorption at −196 °C, and diffuse reflectance spectroscopy. Compared to undoped samples, the introduction of nitrogen in the semiconductor lattice resulted in a shift of band-gap energy to a lower value: 3.0 eV for N-ZnO and 2.35 eV for N-TiO2. The photocatalysts were tested for the degradation of Eriochrome Black T (EBT), which was selected as a model azo dye. Both N-doped semiconductors evidenced an improvement in photocatalytic activity under visible light irradiation (62% and 20% EBT discoloration for N-TiO2 and N-ZnO, respectively) in comparison with the undoped samples, which were inactive in the presence of visible light. Different behavior was observed under UV irradiation. Whereas N-TiO2 was more photoactive than commercial undoped TiO2, the introduction of nitrogen in ZnO wurtzite resulted in a drastic reduction in photocatalytic activity, with only 45% EBT discoloration compared to total color removal obtained with the commercial ZnO sample, suggesting intrinsic limitations for doping of this class of semiconductors.

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Huang, Danhong, T. Apostolova, P. M. Alsing i D. A. Cardimona. "Thermal-drag carrier cooling in undoped semiconductors". Journal of Applied Physics 98, nr 6 (15.09.2005): 063516. http://dx.doi.org/10.1063/1.2041842.

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Hüsser, O. E., H. von Käanel i F. Lévy. "Photoelectrochemistry of Doped and Undoped Semiconductors: A Comparison". Journal of The Electrochemical Society 132, nr 4 (1.04.1985): 810–14. http://dx.doi.org/10.1149/1.2113963.

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Hossein-Babaei, Faramarz, Saeed Masoumi i Amirreza Noori. "Seebeck voltage measurement in undoped metal oxide semiconductors". Measurement Science and Technology 28, nr 11 (12.10.2017): 115002. http://dx.doi.org/10.1088/1361-6501/aa82a4.

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Bonapasta, Aldo Amore. "Theory of H sites in undoped crystalline semiconductors". Physica B: Condensed Matter 170, nr 1-4 (kwiecień 1991): 168–80. http://dx.doi.org/10.1016/0921-4526(91)90120-4.

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Vishnyakov, N. V. "Formation of Potential Barriers in Undoped Disordered Semiconductors". Semiconductors 39, nr 10 (2005): 1147. http://dx.doi.org/10.1134/1.2085261.

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Sikam, Pornsawan, Ruhan Thirayatorn, Thanayut Kaewmaraya, Prasit Thongbai, Pairot Moontragoon i Zoran Ikonic. "Improved Thermoelectric Properties of SrTiO3 via (La, Dy and N) Co-Doping: DFT Approach". Molecules 27, nr 22 (16.11.2022): 7923. http://dx.doi.org/10.3390/molecules27227923.

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This work considers the enhancement of the thermoelectric figure of merit, ZT, of SrTiO3 (STO) semiconductors by (La, Dy and N) co-doping. We have focused on SrTiO3 because it is a semiconductor with a high Seebeck coefficient compared to that of metals. It is expected that SrTiO3 can provide a high power factor, because the capability of converting heat into electricity is proportional to the Seebeck coefficient squared. This research aims to improve the thermoelectric performance of SrTiO3 by replacing host atoms by La, Dy and N atoms based on a theoretical approach performed with the Vienna Ab Initio Simulation Package (VASP) code. Here, undoped SrTiO3, Sr0.875La0.125TiO3, Sr0.875Dy0.125TiO3, SrTiO2.958N0.042, Sr0.750La0.125Dy0.125TiO3 and Sr0.875La0.125TiO2.958N0.042 are studied to investigate the influence of La, Dy and N doping on the thermoelectric properties of the SrTiO3 semiconductor. The undoped and La-, Dy- and N-doped STO structures are optimized. Next, the density of states (DOS), band structures, Seebeck coefficient, electrical conductivity per relaxation time, thermal conductivity per relaxation time and figure of merit (ZT) of all the doped systems are studied. From first-principles calculations, STO exhibits a high Seebeck coefficient and high figure of merit. However, metal and nonmetal doping, i.e., (La, N) co-doping, can generate a figure of merit higher than that of undoped STO. Interestingly, La, Dy and N doping can significantly shift the Fermi level and change the DOS of SrTiO3 around the Fermi level, leading to very different thermoelectric properties than those of undoped SrTiO3. All doped systems considered here show greater electrical conductivity per relaxation time than undoped STO. In particular, (La, N) co-doped STO exhibits the highest ZT of 0.79 at 300 K, and still a high value of 0.77 at 1000 K, as well as high electrical conductivity per relaxation time. This renders it a viable candidate for high-temperature applications.

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Siethoff, H. "Dynamical recovery, dislocation mobility, and diffusion in undoped semiconductors". Physica Status Solidi (a) 138, nr 2 (16.08.1993): 591–99. http://dx.doi.org/10.1002/pssa.2211380227.

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Mittova, Irina Ya, Boris V. Sladkopevtsev i Valentina O. Mittova. "Nanoscale semiconductor and dielectric films and magnetic nanocrystals – new directions of development of the scientific school of Ya. A. Ugai “Solid state chemistry and semiconductors”. Review". Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 23, nr 3 (17.08.2021): 309–36. http://dx.doi.org/10.17308/kcmf.2021.23/3524.

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New directions of development of the scientific school of Yakov Aleksandrovich Ugai “Solid state chemistry and semiconductors” were considered for the direction “Study of semiconductors and nanostructured functional films based on them”, supervised by I. Ya. Mittova. The study of students and followers of the scientific school of Ya. A. Ugai cover materials science topics in the field of solid-state chemistry and inorganic and physical chemistry. At the present stage of research, the emphasis is being placed precisely on nanoscale objects, since in these objects the main mechanisms of modern solid-state chemistry are most clearly revealed: the methods of synthesis - composition - structure (degree of dispersion) - properties. Under the guidance of Professor I. Ya. Mittova DSc (Chem.), research in two key areas is conducted:“Nanoscale semiconductor and dielectric films” and “Doped and undoped nanocrystalline ferrites”. In the first area, the problem of creating high-quality semiconductor and dielectric nanoscale films on AIIIBV by the effect reasonably selected chemostimulators on the process of thermal oxidation of semiconductors and/or directed modification of the composition and properties of the films. They present the specific results achieved to date, reflecting the positive effect of chemostimulators and modifiers on the rate of formation of dielectric and semiconductor films of the nanoscale thickness range and their functional characteristics, which are promising for practical applications.Nanomaterials based on yttrium and lanthanum orthoferrites with a perovskite structure have unique magnetic, optical, and catalytic properties. The use of various approaches to their synthesis and doping allowing to control the structure and properties in a wide range. In the field of magnetic nanocrystals under the supervision of Prof. I. Ya. Mittova studies of the effect of a doping impurity on the composition, structure, and properties of nanoparticles of yttrium and lanthanum orthoferrites by replacing the Y(La)3+ and Fe3+ cations are carried out. In the Socialist Republic of Vietnam one of the talented students of Prof. I. Ya. Mittova, Nguyen Anh Tien, performs studies in this area. To date, new methods for the synthesis ofnanocrystals of doped and undoped ferrites, including ferrites of neodymium, praseodymium, holmium, etc. have been developed.

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Ali, Farida Ashraf, Gouranga Bose, Sushanta Kumar Kamilla, Dilip Kumar Mishra i Priyabrata Pattanaik. "Fabrication and characterization of n-ZnO/p-GaSb heterojunction diode". Microelectronics International 36, nr 4 (7.10.2019): 143–49. http://dx.doi.org/10.1108/mi-01-2019-0002.

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Purpose The purpose of this paper is to examine the growth and characterization of the two different compound semiconductors, namely, n-zinc oxide (ZnO) and p-gallium antimonide (GaSb). In this paper, fabrication and characterization of n-ZnO/p-GaSb heterojunction diode is analyzed. Design/methodology/approach Thermo vertical direction solidification (TVDS) method was used to synthesize undoped GaSb ingot from high purity Ga (5N) and Sb (4N) host materials. Thermal evaporation technique is used to prepare a film of GaSb on glass substrate from the pre-synthesized bulk material by TVDS method. Undoped ZnO film was grown on GaSb film by sol–gel method by using chemical wet and dry (CWD) technique to fabricate n-ZnO/p-GaSb heterojunction diode. Findings The formation of crystalline structure and surface morphological analysis of both the GaSb bulk and film have been carried out by x-ray diffraction (XRD) analysis and scanning electron microscopy analysis. From the XRD studies, the structural characterization and phase identification of ZnO/GaSb interface. The current–voltage characteristic of the n-ZnO/p-GaSb heterostructure is found to be rectifying in nature. Originality/value GaSb film growth on any substrate by thermal evaporation method taking a small piece of the sample from the pre-synthesized GaSb bulk ingot has not been reported yet. Semiconductor device with heterojunction diode by using two different semiconductors such as ZnO/GaSb was used by this group for the first time.

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Williams, J. S., Y. Chen, J. Wong-Leung, A. Kerr i M. V. Swain. "Ultra-micro-indentation of silicon and compound semiconductors with spherical indenters". Journal of Materials Research 14, nr 6 (czerwiec 1999): 2338–43. http://dx.doi.org/10.1557/jmr.1999.0310.

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Details of microindentation of silicon, such as the semiconductor-to-metal transformation, which takes place on loading, have been examined using spherical indenters. Various forms of silicon are studied, including heavily boron-doped wafers and silicon damaged and amorphized by ion implantation as well as material containing dislocations. Results indicate that only silicon, which contains high concentrations of point defects or is amorphous, exhibits mechanical properties that differ significantly from undoped, defect-free crystal. Amorphous silicon exhibits plastic flow under low indentation pressures and does not appear to undergo phase transformation on loading and unloading. Indentation of compound semiconductors is also studied and the load/unload behavior at room temperature is quite different from that of silicon. Both gallium arsenide and indium phosphide, for example, undergo slip-induced plasticity above a critical load.

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Seyidov, MirHasan Yu, Faik A. Mikailzade, Rauf A. Suleymanov, Vafa B. Aliyeva, Tofig G. Mammadov i Galib M. Sharifov. "Polarization switching in undoped and La-doped TlInS2 ferroelectric-semiconductors". Physica B: Condensed Matter 526 (grudzień 2017): 45–53. http://dx.doi.org/10.1016/j.physb.2017.07.003.

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Chaudhuri, Reet, Samuel James Bader, Zhen Chen, David A. Muller, Huili Grace Xing i Debdeep Jena. "A polarization-induced 2D hole gas in undoped gallium nitride quantum wells". Science 365, nr 6460 (26.09.2019): 1454–57. http://dx.doi.org/10.1126/science.aau8623.

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A high-conductivity two-dimensional (2D) hole gas, analogous to the ubiquitous 2D electron gas, is desirable in nitride semiconductors for wide-bandgap p-channel transistors. We report the observation of a polarization-induced high-density 2D hole gas in epitaxially grown gallium nitride on aluminium nitride and show that such hole gases can form without acceptor dopants. The measured high 2D hole gas densities of about 5 × 1013 per square centimeters remain unchanged down to cryogenic temperatures and allow some of the lowest p-type sheet resistances among all wide-bandgap semiconductors. The observed results provide a probe for studying the valence band structure and transport properties of wide-bandgap nitride interfaces.

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Abdullahi, Sabiu Said, Garba Shehu Musa Galadanci, Norlaily Mohd Saiden i Josephine Ying Chyi Liew. "Assessment of Magnetic Properties between Fe and Ni Doped ZnO Nanoparticles Synthesized by Microwave Assisted Synthesis Method". Solid State Phenomena 317 (maj 2021): 119–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.317.119.

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The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.

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Wu, Meirong, Zhiqiang Wei, Wenhua Zhao, Xuan Wang i Jinlong Jiang. "Optical and Magnetic Properties of Ni Doped ZnS Diluted Magnetic Semiconductors Synthesized by Hydrothermal Method". Journal of Nanomaterials 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/1603450.

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Diluted magnetic semiconductors Zn1-xNixS with different consistency ratio (x = 0, 0.01, 0.03, 0.05, and 0.07) were successfully synthesized by hydrothermal method using ethylenediamine as a modifier. The influence of Ni doping concentration on the microstructure, morphology, and optical and magnetic properties of undoped and Ni doped ZnS nanocrystals was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), photoluminescence spectra (PL), and the vibrating sample magnetometer (VSM), respectively. The experiment results show the substitution of Ni2+ on Zn2+ sites without changing the hexagonal wurtzite structure of ZnS and generate single-phase Zn1-xNixS with good crystallization. The lattice constant causes distortion and decreases with the increase of Ni2+ doped concentration. The appearance of the samples is one-dimensional well-dispersed nanorods. UV-vis spectra reveal the band gap of all Zn1-xNixS samples greater than that of bulk ZnS (3.67 eV), and blue shift phenomenon occurs. The photoluminescence spectra of undoped and doped samples possess the broad blue emission band in the range of 400–650 nm; the PL intensities of Zn1-xNixS nanorods increase with the increase of Ni content comparing to pure ZnS and reach maximum for x = 0.03. Magnetic measurements indicated that the undoped ZnS samples are superparamagnetic, whereas the doped samples exhibit ferromagnetism.

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PEARTON, S. J. "HYDROGEN IN CRYSTALLINE SEMICONDUCTORS: PART I—SILICON". International Journal of Modern Physics B 08, nr 09 (20.04.1994): 1093–158. http://dx.doi.org/10.1142/s0217979294000543.

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Hydrogen plays an important role in the properties of Si because of its ability to passivate the electrical activity of shallow dopants and deep level impurities. This passivation can occur during virtually every stage of crystal growth, device fabrication or device operation due to the rapid diffusivity of hydrogen at low temperatures and the fact that it is a component of virtually every gas or liquid that comes in contact with Si. We review the ability of hydrogen to form neutral complexes with dopants and impurities, give examples of hydrogen diffusion profiles in doped and undoped Si, and mention the role of hydrogen during chemical vapor deposition and molecular beam epitaxy of Si.

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Kim, Chang-Hyun. "Bulk versus Contact Doping in Organic Semiconductors". Micromachines 12, nr 7 (24.06.2021): 742. http://dx.doi.org/10.3390/mi12070742.

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This study presents a comparative theoretical analysis of different doping schemes in organic semiconductor devices. Especially, an in-depth investigation into bulk and contact doping methods is conducted, focusing on their direct impact on the terminal characteristics of field-effect transistors. We use experimental data from a high-performance undoped organic transistor to prepare a base simulation framework and carry out a series of predictive simulations with various position- and density-dependent doping conditions. Bulk doping is shown to offer an overall effective current modulation, while contact doping proves to be rather useful to overcome high-barrier contacts. We additionally demonstrate the concept of selective channel doping as an alternative and establish a critical understanding of device performances associated with the key electrostatic features dictated by interfaces and applied voltages.

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Heng, Chenglin, Xuan Wang, Chaonan Zhao, Gang Wu, Yanhui Lv, Hanchun Wu, Ming Zhao i Terje G. Finstad. "Ultrathin Rare-Earth-Doped MoS2 Crystalline Films Prepared with Magnetron Sputtering and Ar + H2 Post-Annealing". Crystals 13, nr 2 (13.02.2023): 308. http://dx.doi.org/10.3390/cryst13020308.

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In this work, we propose a method to prepare large-area, crystalline ultrathin rare-earth (RE, i.e., Eu, Yb, Er and Tb)-doped MoS2 thin films, using magnetron sputtering and subsequent Ar + H2 annealing. The film thickness of as-deposited samples varied from 60 to 100 nm, and decreases to be below 10 nm after annealing at 550 °C for 30 min. X-ray diffraction and Raman spectra analysis revealed that the sample films were crystallized after the annealing, which resulted in a MoS2 crystallite size of about 4–5 nm. X-ray photoelectron spectroscopy indicated that most of the RE ions existed in the films in trivalent states. The optical bandgap of the RE-doped MoS2 samples decreased from 1.6 eV (undoped) to 1.3 eV (Eu-doped) in the UV-vis absorption spectra. Electrical measurements showed that the electrical resistance decreased from 9.13 MΩ (undoped) to 0.34 MΩ (Yb-doped), the carrier density increased by one to two orders of magnitude and the carrier mobility decreased from 5.4 cm2/V·s (undoped) to 0.65 cm2/V·s (Yb-doped). The sign of the Hall coefficients indicated that the undoped MoS2 and the Yb-, Tb- and Er-doped MoS2 samples were n-type semiconductors, while the Eu-doped sample showed p-type characteristics. This study may be helpful to broaden the photoelectronic applications of these two-dimensional materials.

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Freitas, Jr., J. A., i W. J. Moore. "Optical Studies of Undoped and Doped Wide Bandgap Carbide and Nitride Semiconductors". Brazilian Journal of Physics 28, nr 1 (marzec 1998): 12–18. http://dx.doi.org/10.1590/s0103-97331998000100002.

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Sato, Shin-ichiro, Hitoshi Sai, Takeshi Ohshima, Mitsuru Imaizumi, Kazunori Shimazaki i Michio Kondo. "Electric properties of undoped hydrogenated amorphous silicon semiconductors irradiated with self-ions". Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 285 (sierpień 2012): 107–11. http://dx.doi.org/10.1016/j.nimb.2012.05.010.

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Appelbaum, Ian. "Introduction to spin-polarized ballistic hot electron injection and detection in silicon". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, nr 1951 (28.09.2011): 3554–74. http://dx.doi.org/10.1098/rsta.2011.0137.

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Ballistic hot electron transport overcomes the well-known problems of conductivity and spin lifetime mismatch that plague spin injection attempts in semiconductors using ferromagnetic ohmic contacts. Through the spin dependence of the mean free path in ferromagnetic thin films, it also provides a means for spin detection after transport. Experimental results using these techniques (consisting of spin precession and spin-valve measurements) with silicon-based devices reveals the exceptionally long spin lifetime and high spin coherence induced by drift-dominated transport in the semiconductor. An appropriate quantitative model that accurately simulates the device characteristics for both undoped and doped spin transport channels is described; it can be used to recover the transit-time distribution from precession measurements and determine the spin current velocity, diffusion constant and spin lifetime, constituting a spin ‘Haynes–Shockley’ experiment without time-of-flight techniques. A perspective on the future of these methods is offered as a summary.

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Hossein-Babaei, Faramarz, i S. Masoumi. "Electrical Resistance and Seebeck Effect in Undoped Polycrystalline Zinc Oxide". Key Engineering Materials 605 (kwiecień 2014): 185–88. http://dx.doi.org/10.4028/www.scientific.net/kem.605.185.

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Thermoelectric properties of metal oxide semiconductors are of increasing interest in the field of sensors design and fabrication. The oxide components in the majority of such applications are polycrystalline in which the charge transportation is controlled both by the microstructure and the bulk properties of the material. While the dependence of the electrical resistivity on the microstructural and compositional changes in these materials is well understood, the complications encountered with their thermoelectric properties, have remained unattended. Here, we report experimental data on the Seebeck coefficient of undoped polycrystalline zinc oxide measured on the ceramic pellets fabricated by dry pressing of the powder and sintering at 800 and 1000°C, in air. Aluminum ohmic contacts are used for electrical connections. Seebeck voltage and electrical resistivity are measured at various temperatures and different atmospheric condition at the presence of predetermined temperature gradients.

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Knupfer, M., i G. Paasch. "Origin of the interface dipole at interfaces between undoped organic semiconductors and metals". Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 23, nr 4 (lipiec 2005): 1072–77. http://dx.doi.org/10.1116/1.1885021.

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Arslanov, R. K., M. I. Daunov i U. Z. Zalibekov. "Impurity energy spectrum in undoped dilute magnetic p-InAs semiconductors at hydrostatic pressures". Herald of Dagestan State University 33, nr 2 (2018): 51–56. http://dx.doi.org/10.21779/2542-0321-2018-33-2-51-56.

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PERAKIS, I. E., i T. V. SHAHBAZYAN. "CANONICAL TRANSFORMATION APPROACH TO THE ULTRAFAST NONLINEAR OPTICAL DYNAMICS OF SEMICONDUCTORS". International Journal of Modern Physics B 13, nr 08 (30.03.1999): 869–93. http://dx.doi.org/10.1142/s0217979299000734.

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We develop a theory describing the effects of many-particle Coulomb correlations on the coherent ultrafast nonlinear optical response of semiconductors and metals. Our approach is based on a mapping of the nonlinear optical response of the "bare" system onto the linear response of a "dressed" system. The latter is characterized by effective time-dependent optical transition matrix elements, electron/hole dispersions, and interaction potentials, which in undoped semiconductors are determined by the single-exciton and two-exciton Green functions in the absence of optical fields. This mapping is achieved by eliminating the optically-induced charge fluctuations from the Hamiltonian using a Van Vleck canonical transformation. It takes into account all many-body contributions up to a given order in the optical fields as well as important Coulomb-induced quantum dynamics to all orders in the optical field. Our approach allows us to distinguish between optical nonlinearities of different origins and provides a physically-intuitive interpretation of their manifestations in ultrafast coherent nonlinear optical spectroscopy.

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Богацкая, А. В., Н. В. Кленов, П. М. Никифорова, А. М. Попов i А. Е. Щеголев. "Резонансное болометрическое детектирование широкополосных сигналов терагерцевого диапазона частот". Письма в журнал технической физики 47, nr 17 (2021): 50. http://dx.doi.org/10.21883/pjtf.2021.17.51388.18850.

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We discuss the detection of broadband radiation in the terahertz frequency range by a bolometric method using heterostructures consisting of a sequence of conducting and dielectric layers of doped and undoped semiconductors (gallium arsenide, germanium). This structure forms a photonic crystal with allowed and forbidden bands (absorption and transmission ranges). By selecting the thicknesses of the conductive and non-conductive layers and the doping levels, it is possible to form spectral intervals of effective absorption, which allows detecting pulses in the frequency range >10^12 Hz with a spectral width of the order of the carrier frequency.

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Gherras, Hamou, Ahmed Yahiaoui, Aicha Hachemaoui, Abdelkader Belfedal, Abdelkader Dehbi i Andreas Zeinert. "Synthesis and characterization of poly(pyrrole-co-2-nitrocinnamaldehyde) (PPNC), a new copolymer for solar cells applications". Polymers and Polymer Composites 28, nr 4 (9.09.2019): 265–72. http://dx.doi.org/10.1177/0967391119872876.

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The use of conductive polymers as a substitute for metallic conductors and semiconductors has attracted much attention in the literature. In particular, aromatic heterocyclic polymers constitute an important class since they possess chemical and electrical stability in both the oxidized (doped) and neutral (undoped) state. A series of poly(pyrrole- co-2-nitrocinnamaldehyde) were obtained via the condensation of pyrrole and 2-nitrocinnamaldehyde in chloroform using acid exchanged montmorillonite clay called maghnite-H+ as an efficient catalyst. The conjugated copolymer was characterized using proton nuclear magnetic resonance, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy.

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Abdellaziz, I., I. Mellouki, S. Abroug i N. Yacoubi. "Photopyroelectric back detection configuration for thermal diffusivity measurement of undoped and doped GaSb semiconductors". IOP Conference Series: Materials Science and Engineering 28 (7.02.2012): 012001. http://dx.doi.org/10.1088/1757-899x/28/1/012001.

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Kozlov, R. Yu, S. S. Kormilitsina, E. V. Molodtsova i E. O. Zhuravlev. "Growing indium antimonide single crystals with a diameter of 100 mm by the modified Chochralsky method". Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 24, nr 3 (21.09.2021): 190–98. http://dx.doi.org/10.17073/1609-3577-2021-3-190-198.

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At present, all over the world there is a tendency to increase the diameters of single crystals of both elementary semiconductors and semiconductor compounds. There are reports indicating the use of single crystals of III-V semiconductors with a diameter of four to six inches. So far, indium antimonide single crystals up to 75 mm in diameter have been obtained in Russia.Indium antimonide is the element base of the broadest field of solid-state electronics — optoelectronics. On its basis, linear and matrix photodetectors are manufactured, operating in the spectral wavelength range of 3-5 microns, which are used as a viewing element in thermal imaging systems.In this work, we selected the thermal growth conditions and obtained indium antimonide single crystals 100 mm in diameter in the crystallographic direction [100]. The solution of this problem has made it possible to significantly increase the yield of suitable photodetectors.Single crystals 100 mm in diameter were grown by the Czochralski method in a two-stage process. The design of the graphite heating unit was enlarged and matched to a working crucible with a diameter of 150 millimeters and a load of 4.5-5 kg.The Van der Pauw method was used to measure the electrical properties of the obtained single crystals, which corresponded to the standard parameters of undoped indium antimonide. Using an optical microscope, the etching pits were counted using the 9-field method. The dislocation density in crystals with a diameter of 100 mm was ≤ 100 cm-2 and corresponded to the values for crystals of 50 mm.

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Huang, Menglin, Zhengneng Zheng, Zhenxing Dai, Xinjing Guo, Shanshan Wang, Lilai Jiang, Jinchen Wei i Shiyou Chen. "DASP: Defect and Dopant ab-initio Simulation Package". Journal of Semiconductors 43, nr 4 (1.04.2022): 042101. http://dx.doi.org/10.1088/1674-4926/43/4/042101.

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Abstract In order to perform automated calculations of defect and dopant properties in semiconductors and insulators, we developed a software package, the Defect and Dopant ab-initio Simulation Package (DASP), which is composed of four modules for calculating: (i) elemental chemical potentials, (ii) defect (dopant) formation energies and charge-state transition levels, (iii) defect and carrier densities and (iv) carrier dynamics properties of high-density defects. DASP uses the materials genome database for quick determination of competing secondary phases when calculating the elemental chemical potential that stabilizes compound semiconductors. DASP calls the ab-initio software to perform the total energy, structural relaxation and electronic structure calculations of the defect supercells with different charge states, based on which the defect formation energies and charge-state transition levels are calculated. Then DASP can calculate the equilibrium densities of defects and electron and hole carriers as well as the Fermi level in semiconductors under different chemical potential conditions and growth/working temperature. For high-density defects, DASP can calculate the carrier dynamics properties such as the photoluminescence (PL) spectrum and carrier capture cross sections which can interpret the deep level transient spectroscopy (DLTS). Here we will show three application examples of DASP in studying the undoped GaN, C-doped GaN and quasi-one-dimensional SbSeI.

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REDFIELD, DAVID. "DEFECTS IN AMORPHOUS Si:H — THE REHYBRIDIZED TWO-SITE (RTS) MODEL". Modern Physics Letters B 05, nr 14n15 (czerwiec 1991): 933–39. http://dx.doi.org/10.1142/s0217984991001167.

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A comprehensive model for the metastable defects in amorphous Si:H is developed by adapting a recent theory for several kinds of defects in crystalline semiconductors, particularly the DX center in AlGaAs. This new model accounts in a unified way for all of the major observations of defects induced by light, quenching, doping, or compensation; as well as for their anneal. The stretched-exponential time dependence of defect densities with light exposure or annealing, and saturation of the density are also explained. This model is based on foreign atoms rather than on breaking of Si-Si bonds, and in undoped materials it is suggested that unintentional impurities are the source.

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Gaied, Imen, Salima Lassoued, Fredéric Genty i Noureddine Yacoubi. "New Photothermal Deflection Method to Determine Thermal Properties of Bulk Semiconductors". Defect and Diffusion Forum 297-301 (kwiecień 2010): 525–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.525.

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In this paper, we present a new Photothermal Deflection Technique (PTD) to determine thermal properties of bulk doped or undoped semiconductor such as GaAs, GaSb, InAs, etc. The method proposed here consists in covering the sample with a thin graphite layer in order to increase the photothermal signal and to ovoid any reflection on the sample surface. This method deals with the analysis of the logarithm of amplitude and phase variation of the photothermal signal versus square root modulation frequency where the sample placed in air is heated by a modulated light beam coming from a halogen lamp. So the best coincidence between experimental curves and corresponding theoretical ones gives simultaneously the best values of thermal conductivity and thermal diffusivity of the sample. These obtained values are in good agreement with those found in literature. The advantage of applying this method in this way lies in its simplicity and its sensibility to both thermal conductivity and thermal diffusivity.

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Kozlov, Roman Yu, Svetlana S. Kormilitsina, Elena V. Molodtsova i Eugene O. Zhuravlev. "Growth of 100 mm indium antimonide single crystals by modified Czochralski technique". Modern Electronic Materials 7, nr 2 (30.06.2021): 73–78. http://dx.doi.org/10.3897/j.moem.7.2.76286.

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Currently there is a worldwide trend to increase the diameter of crystals grown from elemental semiconductors and semiconductor compounds. According to literary data the diameter of 3–5 semiconductor single crystals grown nowadays is 4 to 6 inches. So far up to 75 mm indium antimonide single crystals have been grown in Russia. Indium antimonide is the element base for the widest field of solid state electronics, i.e., optoelectronics. Indium antimonide is used for the fabrication of 3–5 mm range linear photodetectors and photodetector arrays used as light-sensitive material in heat vision systems. Growth heat conditions have been selected and 100 mm [100] indium antimonide single crystals have been grown using the modified two-stage Czochralski technique. The graphite heating unit has been oversized to accommodate a 150 mm crucible and a 4.5–5 kg load. The results of the work have provided for a substantial increase in the yield of photodetectors. The electrophysical properties of the as-grown single crystals have been studied using the Van der Pau method and proved to be in agreement with the standard parameters of undoped indium antimonide. Using the 9-field etch method of pit counting under an optical microscope the dislocation density in the 100 mm single crystals has been measured to be ≤ 100 cm-2which is similar to that for 50 mm single crystals.

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Kao, Chyuan-Haur, Chia-Shao Liu, Shih-Ming Chan, Chih-Chen Kuo, Shang-Che Tsai, Ming-Ling Lee i Hsiang Chen. "Effects of NH3 Plasma and Mg Doping on InGaZnO pH Sensing Membrane". Membranes 11, nr 12 (20.12.2021): 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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Gan, Zhaofeng, Michael DiNezza, Yong-Hang Zhang, David J. Smith i Martha R. McCartney. "Determination of Mean Inner Potential and Inelastic Mean Free Path of ZnTe Using Off-Axis Electron Holography and Dynamical Effects Affecting Phase Determination". Microscopy and Microanalysis 21, nr 6 (27.11.2015): 1406–12. http://dx.doi.org/10.1017/s1431927615015378.

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AbstractThe mean inner potential (MIP) and inelastic mean free path (IMFP) of undoped ZnTe are determined using a combination of off-axis electron holography and convergent beam electron diffraction. The ZnTe MIP is measured to be 13.7±0.6 V, agreeing with previously reported simulations, and the IMFP at 200 keV is determined to be 46±2 nm for a collection angle of 0.75 mrad. Dynamical effects affecting holographic phase imaging as a function of incident beam direction for several common semiconductors are systematically studied and compared using Bloch wave simulations. These simulation results emphasize the need for careful choice of specimen orientation when carrying out quantitative electron holography studies in order to avoid erroneous phase measurements.

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WANG, HAI-BIN, PING PENG, YUAN-HONG TANG, DAN WANG i LI-MING TANG. "TUNING THE "d0" FERROMAGNETISM IN In2O3 QUANTUM DOTS BY DANGLING BONDS AND VACANCY BASED ON THE FIRST-PRINCIPLE CALCULATION". Modern Physics Letters B 27, nr 10 (26.03.2013): 1350068. http://dx.doi.org/10.1142/s0217984913500681.

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It is difficult to tune the magnetic properties of oxide diluted magnetic semiconductors because of the origin of ferromagnetism (FM) under different versions. Using first-principles band-structure calculations, we find that the surface oxygen dangling bonds and Indium vacancy may be responsible for the unexpected ferromagnetism in undoped In 2 O 3 quantum dots (QDs). The surface oxygen dangling bonds produce a magnetic moment of 6 μB, which primarily distribute on the surface oxygen atoms and an Indium vacancy ( V In ) produce a magnetic moment of 3 μB, which primarily distribute on the six O nearest neighbors of the vacancy center. The origin of the collective magnetic moments are the holes which introduced by the surface oxygen dangling bonds and Indium vacancy.

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Fink, J. "Electronic structure studies of conducting polymers by electron energy-loss spectroscopy". Proceedings, annual meeting, Electron Microscopy Society of America 54 (11.08.1996): 160–61. http://dx.doi.org/10.1017/s0424820100163265.

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Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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Hasan, Sayedul, Mohammad Tanvir Ahmed, Abdullah Al Roman, Shariful Islam i Farid Ahmed. "Investigation of Structural, Electronic, and Optical Properties of Chalcogen-Doped ZrS2: A DFT Analysis". Advances in Materials Science and Engineering 2023 (23.02.2023): 1–10. http://dx.doi.org/10.1155/2023/6525507.

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The electrical and optical characteristics of a ZrS2 monolayer doped with chalcogen atoms (O, Se, or Te), where dopants are introduced by substituting the S atom, are examined on the basis of the density functional theory. The semiconductors pristine ZrS2 and O, Se, and Te-doped ZrS2 monolayers possessed indirect band gaps of 1.187 eV, 1.227 eV, 1.146 eV, and 0.922 eV, respectively. According to the formation energy, the O-doped ZrS2 monolayer is more stable compared to Se-doped and Te-doped ZrS2 monolayers. The optical properties are very similar for both the undoped and doped ZrS2 monolayers. The absorption coefficient and optical conductivity are the highest in the ultraviolet energy region. The designed materials are potentially suitable for UV photodetection and UV filtering applications.

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Lin, Der Yuh, Tung Pai Huang, Fan Lei Wu, Chih Ming Lin, Ying Sheng Huang i Kwong Kau Tiong. "Anisotropy of Photoluminescence in Layered Semiconductors ReS₂ and ReS₂:Au". Solid State Phenomena 170 (kwiecień 2011): 135–38. http://dx.doi.org/10.4028/www.scientific.net/ssp.170.135.

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The optical anisotropy properties of rhenium disulphide (ReS2) and Au-doped rhenium disulphide (ReS2:Au) have been investigated by polarization-dependent photoluminescence (PL). Because the excitonic transitions show strong polarization dependences in the near-infrared region, we used polarization-dependent PL measurements in the range between 0° and 180° to characterize the unique polarization property of ReS2 and ReS2:Au, and identify the origin of the excitonic transitions. It was observed that the variation in the amplitude of PL excitonic transitions with different polarization characteristics follows the Malus rule. In comparison with the undoped ReS2, the PL spectra of Au-doped sample show not only the main excitonic transitions near the direct band edge but also some extra transitions owing to the doping effects.

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Scarfone, Leonard M. "Erratum: Thomas-Fermi-Dirac statistical theory of dispersive dielectric screening in undoped semiconductors at zero temperature". Physical Review B 32, nr 4 (15.08.1985): 2653–55. http://dx.doi.org/10.1103/physrevb.32.2653.

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Ikenoue, Takumi, Satoshi Yoneya, Masao Miyake i Tetsuji Hirato. "Epitaxial Growth and Bandgap Control of Ni1-xMgxO Thin Film Grown by Mist Chemical Vapor Deposition Method". MRS Advances 5, nr 31-32 (2020): 1705–12. http://dx.doi.org/10.1557/adv.2020.219.

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ABSTRACTWide-bandgap oxide semiconductors have received significant attention as they can produce devices with high output and breakdown voltage. p-Type conductivity control is essential to realize bipolar devices. Therefore, as a rare wide-bandgap p-type oxide semiconductor, NiO (3.7 eV) has garnered considerable attention. In view of the heterojunction device with Ga2O3 (4.5–5.0 eV), a p-type material with a large bandgap is desired. Herein, we report the growth of a Ni1-xMgxO thin film, which has a larger bandgap than NiO, on α-Al2O3 (0001) substrates that was developed using the mist chemical vapor deposition method. The Ni1-xMgxO thin films epitaxially grown on α-Al2O3 substrates showed crystallographic orientation relationships identical to those of NiO thin films. The Mg composition of Ni1-xMgxO was easily controlled by the Mg concentration of the precursor solution. The Ni1-xMgxO thin film with a higher Mg composition had a larger bandgap, and the bandgap reached 3.9 eV with a Ni1-xMgxO thin film with x = 0.28. In contrast to an undoped Ni1-xMgxO thin film showing insulating properties, the Li-doped Ni1-xMgxO thin film had resistivities of 101–105 Ω∙cm depending on the Li precursor concentration, suggesting that Li effectively acts as an acceptor.

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Pan, Yongman, Yinzhou Yan, Qiang Wang, Lixue Yang, Xuegang Zhang, Long Tang, Cheng Xing, Fei Chen i Yijian Jiang. "Efficient defect control of zinc vacancy in undoped ZnO microtubes for optoelectronic applications". Journal of Applied Physics 131, nr 10 (14.03.2022): 105105. http://dx.doi.org/10.1063/5.0077884.

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Here, we report a strategy to regulate the defect level of zinc vacancy ( VZn) in acceptor-rich ZnO (A-ZnO) microtubes by optical vapor supersaturated precipitation (OVSP) combined with the first-principles calculation. The formation energy (FE) of VZn in ZnO is calculated based on the density functional theory, indicating the FE of VZn depending upon the surrounding Zn chemical potential in ZnO. The defect level of VZn is experimentally controlled in the A-ZnO microtubes by regulating the concentration of oxygen during the OVSP process. For the high oxygen concentration, the photoluminescence intensity of VZn-related donor–acceptor pair emission is enhanced by 46%, compared with those grown in oxygen-deficient conditions. Meanwhile, a defective 2LA mode appeared in the Raman spectra of A-ZnO microtubes with the increase in oxygen concentration, confirming the controllability of the generation of VZn. The VZn defects induce the conductive filaments for the resistive switching behavior in the A-ZnO microtubes, by which the on/off ratio can be enhanced by up to ∼103. Moreover, the tunable current-induced thermal tunneling electroluminescence was also realized by the defect-controlled A-ZnO microrods/tubes. This work opens new opportunities for the design of novel optoelectronic devices by defect-engineered wide-bandgap semiconductors in future.

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Siyar, Muhammad, Jun-Young Cho, Woo-Chan Jin, Euy Heon Hwang, Miyoung Kim i Chan Park. "Thermoelectric Properties of Cu2SnSe3-SnS Composite". Materials 12, nr 13 (26.06.2019): 2040. http://dx.doi.org/10.3390/ma12132040.

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Heavily doped degenerate semiconductors such as Cu2SnSe3 (CTSe) attracted attention in thermoelectric (TE) and optoelectronic fields, due to their high electrical conductivity and small band gap. The small Seebeck coefficient of undoped CTSe, however, is the major issue in achieving high TE performance (figure of merit, ZT). Here, we report that the Seebeck coefficient of CTSe can be controlled by adding SnS within a CTSe matrix. CTSe-SnS composite has not only high Seebeck coefficient in the range of 300–500 µVolt/K but thermal conductivity which is lower than that of pristine CTSe due to the scattering at the interface between the matrix and the SnS particles. A reasonable ZT of 0.18 is achieved at 570 K by adding a small amount (3 wt.%) of SnS to the CTSe matrix.

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Mathur, Arpit Swarup, Praveen Kumar i B. P. Singh. "Comparative study of absorption band edge tailoring by cationic and anionic doping in TiO2". Materials Science-Poland 36, nr 3 (1.09.2018): 435–38. http://dx.doi.org/10.2478/msp-2018-0060.

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AbstractTitanium dioxide (TiO2) is one of the most favored metal oxide semiconductors for the use as photoanode in photoelectrochemical cells (PEC) splitting the water into hydrogen and oxygen. However, the major impediment is its large bandgap that limits its utilization as photoanode. Doping has evolved as an effective strategy for tailoring optical and electronic properties of TiO2. This paper describes the synthesis of undoped as well as iron (Fe, cationic) and nitrogen (N, anionic) doped nanocrystalline titanium dioxide by sol-gel spin coating method for solar energy absorption in the visible region. All the prepared thin films were characterized by X-ray diffraction and UV-Vis spectroscopy. Doping of both Fe and N into TiO2 resulted in a shift of absorption band edge towards the visible region of solar spectrum.

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Wang, Yanping, Qian Duan, Qingcheng Liang, Gongzheng Yan, Dezhi Yang i Dongge Ma. "A comparative investigation of electron transport properties in Li2CO3 doped and undoped organic semiconductors by admittance spectroscopy". Organic Electronics 66 (marzec 2019): 58–62. http://dx.doi.org/10.1016/j.orgel.2018.12.019.

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Kabalbin, A. N., V. B. Neimash, V. M. Tsmots’ i V. S. Shtym. "Erratum: Diffusion saturation of undoped hydrated amorphous silicon by tin impurity [Semiconductors 32, 263–266 .March 1998]". Semiconductors 32, nr 8 (sierpień 1998): 916. http://dx.doi.org/10.1134/1.1187348.

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Chandramohan, D., i S. Balasubramanian. "Comment on "Thomas-Fermi-Dirac statistical theory of dispersive dielectric screening in undoped semiconductors at zero temperature"". Physical Review B 33, nr 12 (15.06.1986): 8782–84. http://dx.doi.org/10.1103/physrevb.33.8782.

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