Journal articles: 'Sensitive film deposition'

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Eljali, Ahmed, Irwana Nainggolan, Shahrir Hashim, and Tulus Ikhsan Nasution. "Highly Response and Sensitive Copper Sensors Based on Chitosan Films." Advanced Materials Research 1125 (October 2015): 255–59. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.255.

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Discharge of metal containing effluents into water has been a major concern. Traditional detecting methods were proven to be ineffective and expensive. This paper proposes the use of chitosan film as a highly response and sensitive film sensor towards Cu ion due to its positive charge and electrical characteristic. Chitosan film was deposited by using electrochemical deposition technique. Different deposition times were applied to study the effect of deposition time on sensing properties of chitosan films, in which the best performance time of 90 seconds was recorded. This study was carried out to investigate the sensing performance of chitosan films toward variation concentrations of copper ion. Contaminated air exposure technique was used in this work to detect the concentrations of copper ion. The chitosan film sensors showed different sensor output toward deionized water and 0.005 M, 0.01M, 0.05M, 0.1M copper ions. The results showed that chitosan films had good sensitivity, fast response, stable and excellent recovery time. Scanning electron microscopy was employed to characterize chitosan film structure.

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Constantinoiu, Izabela, Dana Miu, and Cristian Viespe. "SAW Hydrogen Sensors with Pd/SnO2 Layers." Materials 15, no. 22 (November 13, 2022): 8012. http://dx.doi.org/10.3390/ma15228012.

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Pd/SnO2 bilayers for surface acoustic wave (SAW) sensors were obtained using pulsed laser deposition (PLD). Bilayers were made at several deposition pressures in order to observe the influence of the morphology of the sensitive films on the response of the sensors. The morphological properties were analyzed by scanning electron microscopy (SEM). The SnO2 monolayers were initially deposited on quartz substrates at 100, 400 and 700 mTorr, to observe their morphology at these pressures. The Pd/SnO2 bilayer depositions were made at 100 and 700 mTorr. The sensors realized with these sensitive films were tested at different hydrogen concentrations, in the range of 0.2–2%, at room temperature. In order to establish selectivity, tests for hydrogen, nitrogen, oxygen and carbon dioxide were carried out with SnO2-700, Pd-100/SnO2-700 and Pd-700/SnO2-700 sensors. The sensor with the most porous sensitive film (both films deposited at 700 mTorr) had the best results: a sensitivity of 0.21 Hz/ppm and a limit of detection (LOD) of 142 ppm. The morphology of the SnO2 film is the one that has the major influence on the sensor results, to the detriment of the Pd morphology. The use of Pd as a catalyst for hydrogen improved the sensitivity of the film considerably and the selectivity of the sensors for hydrogen.

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Eljali, Ahmed, Irwana Nainggolan, Shahrir Hashim, Tulus Ikhsan Nasution, and Nur Zurihan Abd Wahab. "Fabrication of Chitosan-Polyethylene Oxide Polymeric Thin Film Using Electrochemical Deposition for Detection of Volatile Organic Compounds." Key Engineering Materials 744 (July 2017): 359–63. http://dx.doi.org/10.4028/www.scientific.net/kem.744.359.

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This study focused on the fabrication of chitosan-polyethylene oxide sensitive thin film. The polyethylene oxide was used as an additive to enhance the electrical properties of chitosan towards ethanol and methanol gases. The chitosan-polyethylene oxide sensitive film was fabricated using electrochemical deposition technique to deposit a thin film of the sensitive blend on the printed circuit board surface. The sensitive blend electrical (I-V) properties were tested using a specific developed test chamber. Ethanol and methanol volatile organic compound gases were chosen in this work to study the thin sensing properties of the chitosan-polyethylene oxide film. The analyzed data demonstrated that chitosan-polyethylene oxide sensitive film was capable to detect the VOC gas molecules and showed that the sensitive blend was significantly selective to ethanol over methanol gas with output values of 0.31 µA and 0.023 µA respectively. Atomic force microscopy test was used to characterize the morphology and roughness of the pure chitosan and chitosan-polyethylene oxide sensitive films.

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Yunus, Yusniza, Nurul Adlin Mahadzir, Mohamed Nainar Mohamed Ansari, Tg Hasnan Tg Abd Aziz, Atiqah Mohd Afdzaluddin, Hafeez Anwar, Mingqing Wang, and Ahmad Ghadafi Ismail. "Review of the Common Deposition Methods of Thin-Film Pentacene, Its Derivatives, and Their Performance." Polymers 14, no. 6 (March 10, 2022): 1112. http://dx.doi.org/10.3390/polym14061112.

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Pentacene is a well-known conjugated organic molecule with high mobility and a sensitive photo response. It is widely used in electronic devices, such as in organic thin-film transistors (OTFTs), organic light-emitting diodes (OLEDs), photodetectors, and smart sensors. With the development of flexible and wearable electronics, the deposition of good-quality pentacene films in large-scale organic electronics at the industrial level has drawn more research attention. Several methods are used to deposit pentacene thin films. The thermal evaporation technique is the most frequently used method for depositing thin films, as it has low contamination rates and a well-controlled deposition rate. Solution-processable methods such as spin coating, dip coating, and inkjet printing have also been widely studied because they enable large-scale deposition and low-cost fabrication of devices. This review summarizes the deposition principles and control parameters of each deposition method for pentacene and its derivatives. Each method is discussed in terms of experimentation and theory. Based on film quality and device performance, the review also provides a comparison of each method to provide recommendations for specific device applications.

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Kuk, Seoung Woo, Seok Hwan Bang, In Hoe Kim, Sun Yeol Jeon, Hyeong Tag Jeon, Hyung Ho Park, and Ho Jung Chang. "Chemical and Electrical Properties of ZnS Deposited with DEZ and H₂S by Atomic Layer Deposition Method." Materials Science Forum 544-545 (May 2007): 689–92. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.689.

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ZnS thin films were grown by Atomic Layer Deposition (ALD) method with Diethyl- Zinc (DEZ) and hydrogen sulfide (H2S) for the application of a channel layer of OITFT (Organic-Inorganic Thin-Film Transistor). ZnS has many advantages such as high channel mobility, high deposition rate, transparency at room temperature due to the broad band gap (bandgap of ZnS : 3.7 eV), nontoxic characteristic, low resistivity, and less sensitive about oxidation than ZnO. The deposition rate of the ZnS films in our system was about 1.6 Å/cycle. ZnS film was characterized by AES, XRD, Hall-effect measurement.

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Liu, Huan, Shan Shan Wang, Chang Long Cai, and Shun Zhou. "Uncooled Infrared Bolometer Arrays with α-Si and Metal Films." Materials Science Forum 663-665 (November 2010): 421–24. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.421.

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A bolometer with stress equilibrium based on α-Si and metal films is proposed in this paper. The sensitive and support material α-Si films are prepared by plasma enhanced chemical vapor deposition（PECVD）, their stress and deposition rate are studied, and the technological parameter of the low stress and higher temperature coefficient of resistance (TCR) α-Si film are obtained. The result shows that the stress of the α-Si films can be adjusted between positive and negative. Pt films are deposited by electron-beam evaporating equipment. Their square resistance, TCR and stress are tested by four point resistivity test system and film-stress interferometer. The result shows this material is a good heat-sensitive material, and at the same time it can balance the stress of α-Si film. Finally it is found that Pt film is in compressive stress state in the selected technological parameters, and α-Si thin film is in tensile stress state, so the stress of micro-bridge structure can be balanced by this method. In the final, 160×120 infrared micro-bridge array on the wafer and read out integrated circuit (ROIC) chip are successfully fabricated.

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Messier, Russell. "Deposition Processes." MRS Bulletin 13, no. 12 (December 1988): 29–32. http://dx.doi.org/10.1557/s0883769400063661.

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My introduction in the November MRS BULLETIN to this two-part series on deposition processes discussed the extensive use of thin films in science and technology. That it takes two issues and nine articles to cover this topic — and by no means exhaustively — is testimony to the manifold ways thin films are prepared.If all deposition processes resulted in the same product, then such extensive coverage would be redundant and unnecessary. Thin films, however, cover a virtual infinity of free energy states — and related crystal structures, micro-structures, defects, defect densities, impurities, compositions, composition modulations, etc. — that are sensitive to the particular deposition process and its conditions. It is this richness of choice that makes thin film science and technology both exciting and, at times, frustrating.Along with the freedom to extensively vary thin film characteristics, resulting properties and applications comes the difficulty in understanding preparation-characterization-property relations in enough detail to control and reproduce deposition processes.The November articles covered molecular dynamics computer modeling of nucleation and growth processes, molecular beam epitaxy, organometallic vapor phase epitaxy, and chemical vapor deposition. This month's articles continue the sequence of ways to deposit films, the general direction being toward lower substrate temperatures. Plasmas, which offer both increased flexibility and complexity, are primarily considered. The last article covers thermal plasmas, not to control the vapor deposition but to melt powders which result in a multiple splat-quenched array of particles that form coatings important to industry.

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Ryu, Hyun Wook, Yong Joo Park, Hyo Sup Noh, and Jin Seong Park. "Characteristics of SnO₂ Thin Films Deposited by RF Magnetron Sputtering." Materials Science Forum 449-452 (March 2004): 993–96. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.993.

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SnO2 thin films were prepared on SiO2/Si substrate by RF-Magentron Sputtering method, varying the deposition time and Ar-to-O2 flow ratio. The post-annealing was conducted at 500 oC and 700 oC in Ar and O2 atmosphere, respectively. Film characteristics were very sensitive to the gas flow ratio during the deposition and the conditions of post-annealing. The Film thickness decreased with decreasing of Ar flow ratio at a constant amount (50 sccm) of total gas flow. Especially, the film deposited under Ar-O2 mixture gas (Ar-to-O2 ratio of 50%) showed clearly aggregated morphology of small particles (cauliflower) in a wide range of area. In the annealed films, these cauliflowers separated some small grains, decreasing the film thickness.

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Yoshida, Kentaro, Yu Kashimura, Toshio Kamijo, Tetsuya Ono, Takenori Dairaku, Takaya Sato, Yoshitomo Kashiwagi, and Katsuhiko Sato. "Decomposition of Glucose-Sensitive Layer-by-Layer Films Using Hemin, DNA, and Glucose Oxidase." Polymers 12, no. 2 (February 4, 2020): 319. http://dx.doi.org/10.3390/polym12020319.

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Glucose-sensitive films were prepared through the layer-by-layer (LbL) deposition of hemin-modified poly(ethyleneimine) (H-PEI) solution and DNA solution (containing glucose oxidase (GOx)). H-PEI/DNA + GOx multilayer films were constructed using electrostatic interactions. The (H-PEI/DNA + GOx)5 film was then partially decomposed by hydrogen peroxide (H2O2). The mechanism for the decomposition of the LbL film was considered to involve more reactive oxygen species (ROS) that were formed by the reaction of hemin and H2O2, which then caused nonspecific DNA cleavage. In addition, GOx present in the LbL films reacts with glucose to generate hydrogen peroxide. Therefore, decomposition of the (H-PEI/DNA + GOx)5 film was observed when the thin film was immersed in a glucose solution. (H-PEI/DNA + GOx)5 films exposed to a glucose solution for periods of 24, 48 72, and 96 h indicated that the decomposition of the film increased with the time to 9.97%, 16.3%, 23.1%, and 30.5%, respectively. The rate of LbL film decomposition increased with the glucose concentration. At pH and ionic strengths close to physiological conditions, it was possible to slowly decompose the LbL film at low glucose concentrations of 1–10 mM.

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Lima, Roberto R., Leonardo F. Hernandez, Edsion Pecoraro, Estevão Rosim-Fachini, and Maria L. P. da Silva. "Composite Material Sensitive to Volatile Organic Compounds." Materials Science Forum 730-732 (November 2012): 289–94. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.289.

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This work evaluates fluorinated thin films and their composites for sensor development. Composites were produced using 5 µm starch particles and plasma films obtained from organic fluorinated and silicon compounds reactants. Silicon wafers and aluminum trenches were used as substrates. Film thickness, refractive index and chemical structure were also determined. Scanning electron microscopy shows conformal deposition on aluminum trenches. Films deposited on silicon were exposed to vapor of volatile organic compounds and CV curves were obtained. A qualitative model (FemLab 3.2® program) was proposed for the electronic behavior. These environmentally correct films can be used in electronic devices and preferentially reacted to polar compounds. Nonetheless, due to the difficulty in signal recovery, these films are more effective in one-way sensors, in sub-ppm range.

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Constantinoiu, Izabela, Dana Miu, and Cristian Viespe. "Surface Acoustic Wave Sensors for Ammonia Detection at Room Temperature Based on SnO2/Co3O4 Bilayers." Journal of Sensors 2019 (May 19, 2019): 1–6. http://dx.doi.org/10.1155/2019/8203810.

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The selectivity of a SAW (surface acoustic wave) sensor, with a Co3O4 sensitive thin film for NH3 (ammonia) and the influence of SnO2 on its sensitivity, was studied. Thin films were deposited by pulsed laser deposition (PLD) on quartz SAW sensor substrates. Two sensors with different types of sensitive films were developed: a Co3O4 thin film sensor (S1) and a SnO2/Co3O4 thin film sensor (S2). The sensitive films were deposited in conditions which ensured a porous structure. The sensors were tested in the presence of three gases: NH3, methanol, and toluene. The selectivity of Co3O4 for NH3 was determined from the difference in the frequency shifts of the sensor for NH3 and for VOCs (volatile organic compounds). The positive influence of SnO2 on the sensitivity of sensor S2 was observed from the lower limit of detection (LOD) of this sensor and from the differences in frequency shifts between sensor S1 and sensor S2.

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Fernandes, Jessica C., and Marcelo Mulato. "Synthesis and electrical characterization of ZnO and TiO2 thin films and their use as sensitive layer of pH field effect transistor sensors." MRS Proceedings 1675 (2014): 53–58. http://dx.doi.org/10.1557/opl.2014.831.

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ABSTRACTOxide thin films of zinc and titanium materials were deposited by different deposition techniques, to be applied as sensitive layers of pH sensor – EGFET device. The deposition techniques tested were dip-coat, spin-coat, electrodeposition and spray-pyrolysis. The routine and the parameters of each technique were changed aiming optimized the procedures. The pHs buffer solutions tested ranged from 2 to 12. ZnO thin film shows sensitivity about 23 mV/pH, while TiO2 thin films shows only 13.8 mV/pH. The final purpose of this study is to optimize the parameters for each deposition technique for both oxide materials.

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Hanft, Dominik, Murat Bektas, and Ralf Moos. "Powder Pre-Treatment for Aerosol Deposition of Tin Dioxide Coatings for Gas Sensors." Materials 11, no. 8 (August 2, 2018): 1342. http://dx.doi.org/10.3390/ma11081342.

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The Aerosol Deposition (AD) method has the unique property to allow for manufacturing dense ceramic films at room temperature. As found in many publications, the deposition process is very sensitive to powder properties. In particular, powders of nano-sized particles and grains, e.g., from precipitation, are usually beyond the conventional size range of AD processability, yielding chalk-like films of low mechanical stability. Thus, the conventional AD process is limited in applicability. In this study, we try to overcome this problem by adapting the standard milling treatment of powders for improved deposition by additional temperature pre-treatment. Using commercial tin dioxide and including a temperature treatment for grain growth, makes the powder accessible to deposition. In this way, we achieve optically translucent and conductive SnO2 thick films. With the application such as a gas sensitive film as one of many possible applications for SnO2 thick-films, the sensors show excellent response to various reducing gases. This study shows one exemplary way of extending the range of adequate powder and applications for the AD method.

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Kim, Young, Nina Baule, Maheshwar Shrestha, Bocong Zheng, Thomas Schuelke, and Qi Hua Fan. "Single-beam plasma source deposition of carbon thin films." Review of Scientific Instruments 93, no. 11 (November 1, 2022): 113908. http://dx.doi.org/10.1063/5.0102605.

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A single-beam plasma source was developed and used to deposit hydrogenated amorphous carbon ( a-C:H) thin films at room temperature. The plasma source was excited by a combined radio frequency and direct current power, which resulted in tunable ion energy over a wide range. The plasma source could effectively dissociate the source hydrocarbon gas and simultaneously emit an ion beam to interact with the deposited film. Using this plasma source and a mixture of argon and C2H2 gas, a-C:H films were deposited at a rate of ∼26 nm/min. The resulting a-C:H film of 1.2 µm thick was still highly transparent with a transmittance of over 90% in the infrared range and an optical bandgap of 2.04 eV. Young’s modulus of the a-C:H film was ∼80 GPa. The combination of the low-temperature high-rate deposition of transparent a-C:H films with moderately high Young’s modulus makes the single-beam plasma source attractive for many coatings applications, especially in which heat-sensitive and soft materials are involved. The single-beam plasma source can be configured into a linear structure, which could be used for large-area coatings.

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Li, Jin Hua, Meng Zhao, Jiang Bin Su, and Mei Ping Jiang. "Hydrogen Sensing Properties of WO3/Pd Composite Films." Advanced Materials Research 287-290 (July 2011): 2343–46. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2343.

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WO3/Pd layered composite films were prepared by magnetron Sputtering on glass substrate. After deposition, samples were annealed with different condition. The hydrogen sensitive response of the composite film was measured by home-made measurement system. The results indicated that suitable annealing could increase the response sensitivity of the layered composite film to hydrogen detect, Exorbitant annealing temperature will damage Pd layer on the WO3 suface, then decrease the hydrogen detect sinsitivity badly.

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Floro, Jerrold A., Eric Chason, Robert C. Cammarata, and David J. Srolovitz. "Physical Origins of Intrinsic Stresses in Volmer–Weber Thin Films." MRS Bulletin 27, no. 1 (January 2002): 19–25. http://dx.doi.org/10.1557/mrs2002.15.

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AbstractAs-deposited thin films grown by vapor deposition often exhibit large intrinsic stresses that can lead to film failure. While this is an “old” materials problem, our understanding has only recently begun to evolve in a more sophisticated fashion. Sensitive real-time measurements of stress evolution during thin-film deposition reveal a generic compressive–tensile–compressive behavior that correlates with island nucleation and growth, island coalescence, and postcoalescence film growth. In this article, we review the fundamental mechanisms that can generate stresses during the growth of Volmer–Weber thin films. Compressive stresses in both discontinuous and continuous films are generated by surface-stress effects. Tensile stresses are created during island coalescence and grain growth. Compressive stresses can also result from the flux-driven incorporation of excess atoms within grain boundaries. While significant progress has been made in this field recently, further modeling and experimentation are needed to quantitatively sort out the importance of the different mechanisms to the overall behavior.

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Watanabe, Junji, and Mitsugu Hanabusa. "Photochemical vapor deposition of silicon oxynitride films by deuterium lamp." Journal of Materials Research 4, no. 4 (August 1989): 882–85. http://dx.doi.org/10.1557/jmr.1989.0882.

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Silicon oxynitride films have been grown by a photochemical vapor deposition process utilizing VUV light of a deuterium lamp from a gas mixture of Si2H6, NH3, and NO2 at the substrate temperature of about 330 °C. The deposition rate of the film varied with NO2 flow rate and also with the excitation light spectrum which was varied by a low-pass filter of a synthetic or fused silica plate. The composition of the films was sensitive to the NO2 flow rate which was smaller than that of NH3 by a factor of 103.

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Constantinoiu, Izabela, and Cristian Viespe. "Development of Pd/TiO2 Porous Layers by Pulsed Laser Deposition for Surface Acoustic Wave H2 Gas Sensor." Nanomaterials 10, no. 4 (April 15, 2020): 760. http://dx.doi.org/10.3390/nano10040760.

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The influence of sensitive porous films obtained by pulsed laser deposition (PLD) on the response of surface acoustic wave (SAW) sensors on hydrogen at room temperature (RT) was studied. Monolayer films of TiO2 and bilayer films of Pd/TiO2 were deposited on the quartz substrates of SAW sensors. By varying the oxygen and argon pressure in the PLD deposition chamber, different morphologies of the sensitive films were obtained, which were analyzed based on scanning electron microscopy (SEM) images. SAW sensors were realized with different porosity degrees, and these were tested at different hydrogen concentrations. It has been confirmed that the high porosity of the film and the bilayer structure leads to a higher frequency shift and allow the possibility to make tests at lower concentrations. Thus, the best sensor, Pd-1500/TiO2-600, with the deposition pressure of 600 mTorr for TiO2 and 1500 mTorr for Pd, had a frequency shift of 1.8 kHz at 2% hydrogen concentration, a sensitivity of 0.10 Hz/ppm and a limit of detection (LOD) of 1210 ppm. SAW sensors based on such porous films allow the detection of hydrogen but also of other gases at RT, and by PLD method such sensitive porous and nanostructured films can be easily developed.

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Sorokin, Boris, Nikita Asafiev, Dmitry Yashin, Nikolay Luparev, Anton Golovanov, and Konstantin Kravchuk. "Microwave Diamond-Based HBAR as a Highly Sensitive Sensor for Multiple Applications: Acoustic Attenuation in the Mo Film." Sensors 23, no. 9 (May 5, 2023): 4502. http://dx.doi.org/10.3390/s23094502.

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The application of microwave diamond-based HBAR as a sensor of microwave acoustic attenuation α was considered, using the Mo film as an object of research. A multilayered piezoelectric structure, as the Al/Al0.73Sc0.27N/Mo/(100) diamond/Mo, was produced using aluminum–scandium nitride composition, and was studied in detail for a number of the Mo films with different thicknesses obtained by magnetron deposition. The operational frequency band of 3.3 … 18 GHz was used. It was found that the dependence of the resonant frequency shift vs. the h(Mo) thickness for all the overtones to be investigated was linear. For a given sensor, it was found that the mass sensitivity per unit area rm was equal to −26 × 10−12 and −8.7 × 10−12 g/(cm2∙Hz) at 6.0 GHz and 18.3 GHz, respectively. The frequency dependencies of quality factor Q, which changed as a result of Mo film deposition, were considered as the basic experimental data. A method for extracting the α(Mo) values was proposed. The Q-factor under the complete deposition of Mo film was 936 nm, and dropped moderately to ~25%. Such values were enough for an aim of the given experiment. The α(f) in molybdenum was obtained, and demonstrated a dependence that was close to quadratic, corresponding to the Akhiezer attenuation law.

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ASHRAFI, M. MOLLA ALI, H. REZAGHOLIPOUR DIZAJI, M. H. EHSANI, and R. ZAREI MOGHADAM. "ZnS FILM PROPERTIES MODIFICATION USING OBLIQUE ANGLE DEPOSITION TECHNIQUE." Surface Review and Letters 25, no. 06 (August 2018): 1850119. http://dx.doi.org/10.1142/s0218625x18501196.

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In this study, zinc sulfide thin films were deposited on glass substrates at room temperature by vacuum thermal evaporation using oblique angle deposition technique. The samples were prepared at different incident vapor flow angles 0∘, 65∘, and 85∘. The samples were studied using various characterization techniques. The film crystallinity was found very sensitive to the growth angle. Atomic force microscope images of the samples were used to investigate their morphology and surface roughness. The images of samples obtained by the field emission scanning electron microscopy technique showed that the produced samples had columnar structures with columns tilting toward the incident vapor flow direction. Optical constants were calculated by using the data obtained from UV–Vis analysis.

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Guermat, N., A. Bellel, Salah Sahli, Y. Segui, and Patrice Raynaud. "Water Molecule Sensitive Layers Deposited from Hexamethyldisiloxane/Oxygen Mixture at Low Temperature." Materials Science Forum 609 (January 2009): 69–73. http://dx.doi.org/10.4028/www.scientific.net/msf.609.69.

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Humidity sensors are widely used in industry production, process control, environment monitoring, medical and electrical applications. In this study, water molecule sensitive layers have been elaborated by plasma enhanced chemical vapor deposition PECVD technique, from a mixture of hexamethyldisiloxane (HMDSO) and oxygen (O2) in different proportions. The films were deposited on a comb-shape aluminum electrode evaporated on glass substrate. Electrical and structural characteristics of the elaborated humidity sensors were evaluated by humidity-impedance characteristics, infrared spectroscopy FTIR and ellipsometric analysis. Electrical analysis showed that the elaborated humidity sensor exhibited a detectable response to relative humidity ranging from 35 to 95%. However, increasing O2 concentration in the mixture during deposition, leads to a significant decrease of the sensor sensibility. A sensor elaborated with pure vapor of HMDSO exhibited a better sensibility. FTIR analysis revealed that increasing O2 concentration induces a decrease of methyl groups CH3 and the formation of Si-O groups leading to film densification. Besides, the values of the refractive index deduced from ellipsometric data indicated that the refractive index increases with increasing the O2% in the mixture. This observation may be considered as further evidence to film densification.

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Chi, Ning, Hou Qingrun, J. Gao, K. Y. Chan, and D. L. Phillips. "Surface Morphologies of Pulsed Laser Deposited Ultra-Thin Diamond-like Carbon Films." Modern Physics Letters B 11, no. 11 (May 10, 1997): 471–76. http://dx.doi.org/10.1142/s0217984997000578.

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The surface morphologies of pulsed laser deposited ultra-thin diamond-like carbon films were studied by optical microscopy and atomic force microscopy. Off-axis deposited films had a larger size of particulates than on-axis deposited films. The root-mean-squared surface roughness was sensitive to deposition temperature. As a protective coating, the film was deposited on porous silicon. The surface morphology of the porous silicon changed considerably after carbon coating.

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Kim, Du-Yun, Ji-Hye Kwon, Gil-Su Jang, and Nong-Moon Hwang. "Effect of Pressure on the Film Deposition during RF Magnetron Sputtering Considering Charged Nanoparticles." Coatings 11, no. 2 (January 26, 2021): 132. http://dx.doi.org/10.3390/coatings11020132.

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Non-classical crystallization, in which charged nanoparticles (NPs) are the building blocks of film growth, has been extensively studied in chemical vapor deposition (CVD). Recently, a similar mechanism of film growth has been reported during radio frequency (RF) sputtering with a Ti target and DC magnetron sputtering using an Ag target. In this study, the effect of pressure on the generation of Ti NPs and on the film deposition was studied during RF sputtering with a Ti target. Ti NPs were captured on transmission electron microscopy (TEM) membranes with the electric biases of −30, 0, and +50 V under 20 and 80 mTorr. The number densities of the Ti NPs were 134, 103, and 21 per 100 × 100 nm2, respectively, with the biases of −30, 0, and +50 V under 20 mTorr and were 196, 98, and 0 per 100 × 100 nm2, respectively, with the biases of −30, 0, and +50 V under 80 mTorr, which was analyzed by TEM. The growth rate of Ti films deposited on Si substrates was insensitive to the substrate bias under 20 mTorr but was sensitive under 80 mTorr, with the thicknesses of 132, 133, 97, and 29 nm, respectively, after being deposited for 15 min with the substrate biases of −30, −10, 0, and +50 V. This sensitive dependence of the film growth rate on the substrate bias under 80 mTorr is in agreement with the sensitive dependence of the number density of Ti NPs on the substrate bias under 80 mTorr.

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RAKOV, NIKIFOR, ARSHAD MAHMOOD, and MUFEI XIAO. "DEPOSITION-AND-SUBSTRATE TUNABLE PHOTONIC BANDGAP IN OPTICAL RESPONSES OF HYDROGENATED AMORPHOUS SILICON CARBIDE THIN FILMS." Modern Physics Letters B 17, no. 09 (April 20, 2003): 387–92. http://dx.doi.org/10.1142/s0217984903005305.

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Amorphous hydrogenated silicon carbide (a-SiC:H) thin films have been prepared by the RF reactive magnetron sputtering technique. The optical properties of the films have been studied by optical spectroscopy with an incoherent light source. The material is commonly regarded as a dielectric. We have discovered however that some films that were prepared under certain deposition conditions and on certain substrates may respond to external light as a metallic thin film, i.e. there are strongly enhanced reflection peaks in the optical spectrum. We have further discovered that some films may have a strong and broadened absorption peak at about 590 nm, which is an apparent photonic bandgap in the visible spectrum. The appearance of the photonic bandgap is very sensitive to two parameters: the substrate and the deposition gas. By changing the two parameters, one shifts the status of the film from with and without the photonic bandgap.

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Haruta, Yuki, Takumi Ikenoue, Masao Miyake, and Tetsuji Hirato. "Fabrication of CsPbBr3 Thick Films by Using a Mist Deposition Method for Highly Sensitive X-ray Detection." MRS Advances 5, no. 8-9 (2020): 395–401. http://dx.doi.org/10.1557/adv.2020.8.

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AbstractX-ray imaging is a valuable technique used for medical imaging and non-destructive inspection of industrial products. However, the radiation may put humans at risk of developing cancer. Consequently, highly sensitive X-ray detectors, which enable X-ray imaging at a low dose rate, are required. Metal halide perovskite materials have demonstrated excellent X-ray detection performance including a high sensitivity owing to their high absorption coefficient, high carrier mobility, and long carrier lifetime. However, perovskite thick films with a large area, which is essential to realize the application of such materials to X-ray imaging devices have not been extensively investigated. To this end, in this study, a polymer is employed as a buffer layer to avoid film exfoliation, which makes it difficult to fabricate perovskite thick films, and a 110-μm-thick CsPbBr3 film is successfully obtained using a scalable solution method. In addition, an X-ray detector based on the CsPbBr3 thick film is fabricated, which demonstrates a sensitivity of 11,840 μC Gyair–1 cm–2. This sensitivity is approximately 600 times higher than that of the existing commercial a-Se X-ray detectors.

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Yoshida, Kentaro, Tetsuya Ono, Takenori Dairaku, Yoshitomo Kashiwagi, and Katsuhiko Sato. "Preparation of Hydrogen Peroxide Sensitive Nanofilms by a Layer-by-Layer Technique." Nanomaterials 8, no. 11 (November 15, 2018): 941. http://dx.doi.org/10.3390/nano8110941.

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H2O2-sensitive nanofilms composed of DNA and hemin-appended poly(ethyleneimine) (H-PEI) were prepared by a layer-by-layer deposition of DNA and H-PEI through an electrostatic interaction. The (H-PEI/DNA)5 film was decomposed by addition of 10 mM H2O2. H2O2-induced decomposition was also confirmed in the hemin-containing (PEI/DNA)5 in which hemin molecules were adsorbed by a noncovalent bond to the nanofilm. On the other hand, the (PEI/DNA)5 film containing no hemin and the (H-PEI/PSS)5 film using PSS instead of DNA did not decompose even with 100 mM H2O2. The mechanism of nanofilm decomposition was thought that more reactive oxygen species (ROS) was formed by reaction of hemin and H2O2 and then the ROS caused DNA cleavage. As a result (H-PEI/DNA)5 and hemin-containing (PEI/DNA)5 films were decomposed. The decomposition rate of these nanofilms were depended on concentration of H2O2, modification ratio of hemin, pH, and ionic strength.

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Muralter, Fabian, Alberto Perrotta, and Anna Maria Coclite. "Thickness-Dependent Swelling Behavior of Vapor-Deposited Hydrogel Thin Films." Proceedings 2, no. 13 (December 3, 2018): 757. http://dx.doi.org/10.3390/proceedings2130757.

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Hydrogel thin films containing temperature sensitive chemical functionalities (such as N-isopropylacrylamide, NIPAAm) are particularly interesting for sensor and actuator setups. Complex 3D structures can be conformally coated by the solvent free technique initiated Chemical Vapor Deposition, with precise control over chemical composition and film thickness. In this study, NIPAAm-based thin films with film thicknesses ranging from tens to several hundreds of nanometers and with different amounts of cross-linking were deposited. Above the lower critical solution temperature (LCST), these films repel out water and hence shrink. The amount of cross-linking and the deposited film thickness were successfully identified to both affect shape and position of the LCST transition of these systems: a promising basis for tuning response properties.

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Mustata, Ion, Cristian Lungu, Ionut Jepu, and Corneliu Porosnicu. "Thermionic Vacuum Discharges for Thin Film Depositions." Coatings 13, no. 9 (August 25, 2023): 1500. http://dx.doi.org/10.3390/coatings13091500.

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The thermionic vacuum discharge method is very effective in that the films obtained using this technology are characterised by a very high degree of adhesion, density and purity because the deposition technique is carried out in high, very high or, if possible, in ultra-very high vacuum conditions with no gas present. When the substrate is placed in vacuum, no heat transfer particles are present, the substrate being heated only by the ion incident on the surface. This advantage recommends the TVD method for deposits on plastics or other thermally sensitive materials. Additionally, this slow heat transfer reduces energy loss, making the deposition method industrially competitive. The paper aims to present theoretical aspects of this type of discharge, compared to typical or more popular plasmas but also to present the achievements of this method and its utility in the thin films production, layers that have specific imposed properties. The practical depositions and applications presented are in the nuclear fusion-related material science and also for obtaining materials for granular structures, used as magneto-resistive coatings.

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Pratap Deshmukh, Sachin Shendokar, and Jag Sankar. "Fabrication of Mg/Al2O3 Nanolaminates using DC/PDC Magnetron Sputtering to Evaluate the Effect of Oxygen Content and Total Pressure for Deposition of Thin-Films." Global Journal of Engineering and Technology Advances 15, no. 1 (April 30, 2023): 102–9. http://dx.doi.org/10.30574/gjeta.2023.15.1.0074.

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Thin films have always shown high sensitivity to its deposition parameters and surface morphology. Magnetron sputtering is known for its high level of consistency in deposition and repeatability. In this study Mg/Al2O3 nanolaminates in a range of 10 to 40 nm were synthesized using Direct current and Pulsed DC sputtering techniques at room temperature on glass substrates and silicon substrate using different oxygen flow rates and varying total pressure conditions to understand its effect on deposition rates and roughness of thin films. It is observed that more power and resources consumed for higher deposition time. Roughness of the film is very sensitive for certain applications like corrosion, Lenses, Implants. Scanning electron microscopy (SEM), Atomic force microscopy (AFM) were used to characterize the morphology, structure of the thin films. Optical microscopy and X-ray reflectometry (XRD-XRR) techniques confirmed the optical density and thickness of the nanolaminates respectively. It is confirmed that as total pressure and oxygen flow rate rises deposition rate significantly goes down, that impacts deposition time and roughness of thin films.

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Zheng, Yiran, Min Li, Xiaoyan Wen, Ho-Pui Ho, and Haifei Lu. "Nanostructured ZnO/Ag Film Prepared by Magnetron Sputtering Method for Fast Response of Ammonia Gas Detection." Molecules 25, no. 8 (April 20, 2020): 1899. http://dx.doi.org/10.3390/molecules25081899.

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Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In general, an extremely thin silver (Ag) layer (1, 3, 5 nm) and a 100 nm ZnO film are sequentially deposited on the SiO2/Si substrate by a magnetron sputtering method. The porous nanostructure of ZnO film is formed after thermal annealing contributed by the diffusion of Ag among ZnO crystal grains and the expansion of the ZnO film. Different thicknesses of the Ag layer help the formation of different sizes and quantities of hollows uniformly distributed in the ZnO film, which is demonstrated to hold superior gas sensing abilities than the compact ZnO film. The responses of the different porous ZnO films were also investigated in the ammonia concentration range of 10 to 300 ppm. Experimental results demonstrate that the ZnO/Ag(3 nm) sensor possesses a good electrical resistance variation of 85.74% after exposing the sample to 300 ppm ammonia gas for 310 s. Interestingly, a fast response of 61.18% in 60 s for 300 ppm ammonia gas has been achieved from the ZnO/Ag(5 nm) sensor, which costs only 6 s for the response increase to 10%. Therefore, this controllable, porous, nanostructured ZnO film maintaining a sensitive gas response, fabricated by the physical deposition approach, will be of great interest to the gas-sensing community.

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31

Perraudeau, Amélie, Christelle Dublanche-Tixier, Pascal Tristant, Christophe Chazelas, Sylvain Vedraine, and Bernard Ratier. "Low-temperature deposition of TiO2 by atmospheric pressure PECVD towards photoanode elaboration for perovskite and solid-state dye-sensitized solar cells." EPJ Photovoltaics 10 (2019): 5. http://dx.doi.org/10.1051/epjpv/2019006.

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An original low-temperature atmospheric pressure plasma-enhanced chemical vapor deposition process was used to deposit titanium dioxide thin films. The parametric study in dynamic mode deposition aimed at growing an ideal columnar film composed of aligned anatase monocrystals as solar cell photoanode, previously obtained on silicon wafers in static mode deposition. A process parameters optimization was necessary to deposit onto thermally sensitive glass/FTO substrates. In this paper, the morphology, crystallinity and optical transmission of the coatings have been studied. The coatings display a columnar cauliflower-like structure, composed of TiO2 amorphous particles assembly. After deposition, the light transmission properties of the substrate were reduced. As a solution, an ultrasound bath cleaning was set up to enhance the transmitted light through the photoanode.

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32

Pour, Ghobad Behzadi, Leila Fekri Aval, and Shahnaz Eslami. "Sensitive Capacitive-type Hydrogen Sensor Based on Ni Thin Film in Different Hydrogen Concentrations." Current Nanoscience 14, no. 2 (February 1, 2018): 136–42. http://dx.doi.org/10.2174/1573413713666171002124909.

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Background: Hydrogen sensors are micro/nano-structure that are used to locate hydrogen leaks. They are considered to have fast response/recovery time and long lifetime as compared to conventional gas sensors. In this paper, fabrication of sensitive capacitive-type hydrogen gas sensor based on Ni thin film has been investigated. The C-V curves of the sensor in different hydrogen concentrations have been reported. Method: Dry oxidation was done in thermal chemical vapor deposition furnace (TCVD). For oxidation time of 5 min, the oxide thickness was 15 nm and for oxidation time 10 min, it was 20 nm. The Ni thin film as a catalytic metal was deposited on the oxide film using electron gun deposition. Two MOS sensors were compared with different oxide film thickness and different hydrogen concentrations. Results: The highest response of the two MOS sensors with 15 nm and 20 nm oxide film thickness in 4% hydrogen concentration was 87.5% and 65.4% respectively. The fast response times for MOS sensors with 15 nm and 20 nm oxide film thickness in 4% hydrogen concentration was 8 s and 21 s, respectively. Conclusion: By increasing the hydrogen concentration from 1% to 4%, the response time for MOS sensor (20nm oxide thickness), was decreased from 28s to 21s. The recovery time was inversely increased from 237s to 360s. The experimental results showed that the MOS sensor based on Ni thin film had a quick response and a high sensitivity.

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Myasoedova, Tatiana N., Mikhail N. Grigoryev, Nina K. Plugotarenko, and Tatiana S. Mikhailova. "Fabrication of Gas-Sensor Chips Based on Silicon–Carbon Films Obtained by Electrochemical Deposition." Chemosensors 7, no. 4 (October 30, 2019): 52. http://dx.doi.org/10.3390/chemosensors7040052.

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In this study, we designed two types of gas-sensor chips with silicon–carbon film, doped with CuO, as the sensitive layer. The first type of gas-sensor chip consists of an Al2O3 substrate with a conductive chromium sublayer of ~10 nm thickness and 200 Ω/□ surface resistance, deposited by magnetron sputtering. The second type was fabricated via the electrochemical deposition of a silicon–carbon film onto a dielectric substrate with copper electrodes formed by photoelectrochemical etching. The gas sensors are sensitive to the presence of CO and CH4 impurities in the air at operating temperatures above 150 °C, and demonstrated p- (type-1) and n-type (type-2) conductivity. The type-1 gas sensor showed fast response and recovery time but low sensitivity, while the type-2 sensor was characterized by high sensitivity but longer response and recovery time. The silicon–carbon films were characterized by the presence of the hexagonal 6H SiC polytype with the impurities of the rhombohedral 15 R SiC phase. XRD analysis revealed the presence of a CuO phase.

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Rahman, Rohanieza Abdul, Muhammad Al Hadi Zulkefle, Wan Fazlida Hanim Abdullah, and Sukreen Hana Herman. "Effect of Post Deposition Annealing Process on the pH Sensitivity of Spin-Coated Titanium Dioxide Thin Film." Applied Mechanics and Materials 749 (April 2015): 197–201. http://dx.doi.org/10.4028/www.scientific.net/amm.749.197.

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This paper presents an investigation on titanium dioxide (TiO2) thin film, which is used as sensing membrane for Extended-Gate Field Effect Transistor (EGFET) for pH sensing application. TiO2 thin films were deposited using sol-gel spin coating method on indium tin oxide (ITO) substrates. After the deposition, the thin films were annealed at 300 °C for 10 and 15 min, while another sample was annealed at 400 °C for 15 min. The sensitivity measurement was taken using the EGFET setup equipment with constant-current (100 μA) and constant-voltage (0.5 V) biasing interfacing circuit. TiO2 thin film as the pH-sensitive membrane and the working electrode was connected to a commercial metal-oxide semiconductor FET (MOSFET). The MOSFET then was connected to the interfacing circuit. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. For comparison, a sample of bare-ITO was also tested to see its sensitivity. We found that the TiO2 thin film annealed at 400 °C for 15 min gave the highest sensitivity compared to other annealing conditions and also compared to the bare ITO substrate with the value of 44.30 mV/pH. This showed that TiO2 thin film can be used for pH sensing and the post-deposition treatment of the thin film can influence the sensing ability. We also measured the TiO2 thin films’ current – voltage (I-V) characteristics. Relating the I-V characteristic of the thin films and sensitivity, the sensing membrane with higher conductivity gave better sensitivity.

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Shendage, Sambhaji S., Vithoba L. Patil, Sharadrao A. Vanalakar, Sarita P. Patil, Jalindar L. Bhosale, Jin H. Kim, and Pramod S. Patil. "Characterization and Gas Sensing Properties of Spin Coated WO3 Thin Films." Zeitschrift für Physikalische Chemie 234, no. 11-12 (December 16, 2020): 1819–34. http://dx.doi.org/10.1515/zpch-2018-1293.

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AbstractThe WO3 thin films have been synthesized on to the glass substrates by a simple and easy spin coating method at different deposition cycles and their sensor responses towards various concentrations of NO2 gas were investigated. The WO3 films were spin coated at a spinning rate of 2500–3000 rpm for 5, 10 and 15 deposition cycles, respectively. Then the films were annealed at 400 °C for 1 h in a furnace. The structural, morphological, optical and electrical properties of WO3 films were studied by different characterization techniques such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), FT-RAMAN Spectroscopy and electrical resistivity measurements by laboratory made two probe method respectively. It reveals a spherical grain – like morphology with a pure monoclinic phase of WO3. The FT-RAMAN spectra also confirm the pure monoclinic phase of WO3. The WO3-10 film sensor exhibits maximum gas sensitivity 21.93 and 102.4% to 5 and 100 ppm NO2 at 200 °C, respectively. The WO3-10 thin film sensors is highly sensitive and selective to NO2 over other gases.

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Zhao, Min, Hongyi Tang, Ziwei Liu, Zhaoyang Tong, and Zhimei Qi. "A Surface-Scattering-Based Composite Optical Waveguide Sensor for Aerosol Deposition Detection." Chemosensors 10, no. 12 (December 15, 2022): 535. http://dx.doi.org/10.3390/chemosensors10120535.

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Aerosol is a suspension of fine chemical or biological particles in the air, and it is harmful, easily causing air pollution, respiratory diseases, infrastructure corrosion, and poor visibility. Therefore, the development of advanced optical sensors for real-time detection of aerosol deposition is of great significance. In this work, a prism-coupled composite optical waveguide (COWG) sensor for aerosol deposition detection based on surface scattering is proposed and demonstrated theoretically and experimentally. The COWG consists of a single-mode slab glass waveguide locally covered with a tapered thin film of high-index metal oxide. The tapered film can greatly enhance the evanescent field through the adiabatic transition of the fundamental transverse electric (TE0) mode between the uncovered and film-covered regions, thereby enabling the COWG to serve as a simple yet highly sensitive evanescent-wave scattering sensor for sensitive detection of aerosol deposition. The COWG with a tapered layer of Ta2O5 was prepared by masked sputtering, aerosol salt particle deposition on the COWG was successfully detected, and the influence of surface water droplets on the COWG sensor performance was analyzed. The experimental results indicate that the sensitivity of the COWG is 30 times higher than that of the bare glass waveguide.

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Tedzhetov, Valentin A., Elena N. Sheftel, Eugene V. Harin, and Philipp V. Kiryukhantsev-Korneev. "Residual Stresses in Soft Magnetic FeTiB and FeZrN Films Obtained by Magnetron Deposition." Coatings 11, no. 1 (December 31, 2020): 34. http://dx.doi.org/10.3390/coatings11010034.

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The coercive field of soft magnetic ferromagnets is a structure-sensitive property and, in particular, is substantially affected by residual stresses. In the present study, the phase and structural states and residual stresses of the FeTiB and FeZrN films of various compositions, which were prepared by magnetron deposition on glass substrates and subsequent 1-h annealing at temperatures of 200–600 °C, were investigated by X-ray diffraction. The formation of a nanocrystalline structure is observed. It comprises different phases having different lattice parameters and unit-cell volumes and is characterized by high level of microstrains of grains as well; the microstrains predetermine the formation of high compressive stresses in the deposited films. As the annealing temperature increases, the compressive stresses decrease, and, at certain temperatures, gradually the films transform into thermal tensile stresses, which are induced by the difference in the thermal expansion coefficients of the film and substrate. Thus, the heat treatment is the efficient way to improve the soft magnetic properties of the studied class of film materials produced by magnetron deposition.

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38

Gao, Qun, Hao Yang, Cuichen Hu, Zhiwen He, Hua Lu, Wending Zhang, Dong Mao, Ting Mei, and Jianlin Zhao. "Physical vapor deposition of large-scale PbSe films and its applications in pulsed fiber lasers." Nanophotonics 9, no. 8 (November 30, 2019): 2367–75. http://dx.doi.org/10.1515/nanoph-2019-0380.

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AbstractLead selenide (PbSe) is a new emerging semiconductor with layer-dependent bandgap that has attracted much interest due to its high infrared response and good environmental stability. We have prepared large-scale PbSe films with the area of 7 cm2 and thickness of 25 nm based on physical vapor deposition approach at 160°C. The PbSe films exhibit saturable absorption property at 1.55 μm and a polarization-sensitive saturable absorber is obtained by growing PbSe on D-shaped fiber. Single-pulse with the duration of 490 fs is generated at the pump of 12 mW and the mode-locking operation is maintained at the pump of 1500 mW, indicating the high damage threshold of the D-shaped fiber based saturable absorber. Two polarization-insensitive saturable absorbers are achieved by depositing PbSe on fiber facet and polyvinyl alcohol film, respectively. For fiber facet (polyvinyl alcohol film) based saturable absorber, the repetition rate of Q-switched pulses increases from 8.6 (16.3) kHz to 45.4 (59.2) kHz while the duration decreases from 7.92 (12) μs to 2.06 (3.12) μs by tuning the pump from 15 mW to 90 (60) mW. Such large-scale PbSe films possess features of low cost and high modulation ability, and can find important applications in infrared optical modulators and detectors.

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Kovalchuk, A. A. "Structure and oxygen-sensitive properties of thin films of natural carbon." Journal of Physics: Conference Series 2316, no. 1 (August 1, 2022): 012014. http://dx.doi.org/10.1088/1742-6596/2316/1/012014.

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Abstract Thin film carbon nanomaterials are widely studied and used as functional, conductive, reflective, and sensor coatings. In this work, films of natural graphene-based carbon are studied as a sensitive material for a gas sensor operating close to room temperature. The structural features of the films were studied by scanning electron microscopy and Raman spectroscopy. It has been found that the deposition of natural carbon on substrates with a conductive coatings of indium oxide and of indium tin oxide allows to obtain a thin films, represented by homogeneous carbon nets, in the nodes of which are globular nano-sized particles. Microwave conductivity measurements were carried out using a λ/4 coaxial resonator based on a symmetric two-wire line. The results demonstrated that films on substrates with deposited indium oxide and indium tin oxide desorb oxygen from various structural levels of graphene-based carbon.

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Lőrinczi, Adam, Eugenia Fagadar-Cosma, Gabriel Socol, Andreea Mihăilescu, Elena Matei, Florinel Sava, and Mariana Ştefan. "SnSe2-Zn-Porphyrin Nanocomposite Thin Films for Threshold Methane Concentration Detection at Room Temperature." Chemosensors 8, no. 4 (December 18, 2020): 134. http://dx.doi.org/10.3390/chemosensors8040134.

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Nanocomposite thin films, sensitive to methane at the room temperature (25–30 °C), have been prepared, starting from SnSe2 powder and Zn(II)-5,10,15,20-tetrakis-(4-aminophenyl)- -porphyrin (ZnTAPP) powder, that were fully characterized by XRD, UV-VIS, FT-IR, Nuclear Magnetic Resonance (1H-NMR and 13C-NMR), Atomic Force Microscopy (AFM), SEM and Electron Paramagnetic Resonance (EPR) techniques. Film deposition was made by drop casting from a suitable solvent for the two starting materials, after mixing them in an ultrasonic bath. The thickness of these films were estimated from SEM images, and found to be around 1.3 μm. These thin films proved to be sensitive to a threshold methane (CH4) concentration as low as 1000 ppm, at a room temperature of about 25 °C, without the need for heating the sensing element. The nanocomposite material has a prompt and reproducible response to methane in the case of air, with 50% relative humidity (RH) as well. A comparison of the methane sensing performances of our new nanocomposite film with that of other recently reported methane sensitive materials is provided. It is suitable for signaling gas presence before reaching the critical lower explosion limit concentration of methane at 50,000 ppm.

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Navale, S. T., A. T. Mane, M. A. Chougule, N. M. Shinde, JunHo Kim, and V. B. Patil. "Highly selective and sensitive CdS thin film sensors for detection of NO2 gas." RSC Adv. 4, no. 84 (2014): 44547–54. http://dx.doi.org/10.1039/c4ra06531j.

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Mazur, Piotr, Agata Sabik, Rafał Lewandków, Artur Trembułowicz, and Miłosz Grodzicki. "Obtaining Niobium Nitride on n-GaN by Surface Mediated Nitridation Technique." Crystals 12, no. 12 (December 18, 2022): 1847. http://dx.doi.org/10.3390/cryst12121847.

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In this work the n-GaN(1000) surface is used as a source of nitrogen atoms in order to obtain niobium nitride film by a surface-mediated nitridation technique. To this end, the physical vapor deposition of the niobium film on GaN is followed by sample annealing at 1123 K. A thermally induced decomposition of GaN and interfacial mixing phenomena lead to the formation of a niobium nitride compound, which contains Nb from thin film and N atoms from the substrate. The processes allowed the obtaining of ordered NbNx films on GaN. Structural and chemical properties of both the GaN substrate and NbNx films were studied in-situ by surface-sensitive techniques, i.e., X-ray and UV photoelectron spectroscopies (XPS/UPS) and a low-energy electron diffraction (LEED). Then, the NbNx/GaN surface morphology was investigated ex-situ by scanning tunneling microscopy (STM).

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Shu, Lin, Xuemin Wang, Dawei Yan, Long Fan, and Weidong Wu. "The Investigation of High-Temperature SAW Oxygen Sensor Based on ZnO Films." Materials 12, no. 8 (April 15, 2019): 1235. http://dx.doi.org/10.3390/ma12081235.

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In this paper, a wireless oxygen sensor based on a surface acoustic wave (SAW) was reported. For high-temperature applications, novel Al2O3/ZnO/Pt multilayered conductive film was deposited on langasite substrate as the electrodes, and ZnO film obtained by the pulse laser deposition (PLD) method was used as the sensitive film. The measurements of X-ray diffraction (XRD) and a scanning electron microscope (SEM) showed that the c-axis orientation of the ZnO grains and the surface morphology of the films were regulated by the deposition temperature. Meanwhile, the gas response of the sensor was strongly dependent on the surface morphology of the ZnO film. The experimental results showed that the oxygen gas sensor could operate at a high-temperature environment up to 850 °C with good stability for a long period. The max frequency shift of the sensors reaches 310 kHz, when exposed to 40% O2 gas at 850 °C. The calculated standard error of the sensors in a high-temperature measurement process is within 3%. Additionally, no significant signal degradation could be observed in the long-term experimental period. The prepared SAW oxygen gas sensor has potential applications in high-temperature sensing systems.

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Dai, Xingze, Jing Guo, Tongbin Huang, Dong Ding, and Chao Wang. "Magnetic Sensing Properties of PVD Carbon Films Containing Vertically Aligned Crystallites." Sensors 19, no. 19 (September 30, 2019): 4248. http://dx.doi.org/10.3390/s19194248.

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The demands for magnetic sensors are uprising due to the rapid development of smart equipments and internet of things. Exploring magnetic sensitive materials which are easily obtainable and of low cost thereby become of great significance. Carbon film with crystallized features was recently reported with room-temperature ferro-magnetism and magnetoresistance, owing to its spin–orbital interactions at the graphene edges and temperature-depending carrier transport properties. Such phenomena indicate that the film can serve as a novel magnetic sensitive material. In this study, carbon films with vertically aligned nano-crystallites were obtained by a plasma-assisted physical vapor deposition (PVD) method. Basic test circuits were built on the films, and the sensing properties were investigated in external magnetic fields with different intensities and relative angles to the films surface. The results showed that the carbon-based sensing devices were capable to work in the temperature region of 250–400 K. The minimum field intensity and angle change to which the device can respond were 1 mT and 2°. By substrate-introduced enhancement, the maximum changing-rate of the film resistance could reach to 1100%/T. This research pointed out a practical and simple way to build magnetic sensors with PVD carbon films.

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Cougnon, Florian, Mathias Kersemans, Wim Van Paepegem, and Diederik Depla. "Sputter Deposited Metal Layers Embedded in Composites—From Fundamentals to Applications." Coatings 11, no. 2 (February 6, 2021): 190. http://dx.doi.org/10.3390/coatings11020190.

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Due to the low heat flux towards the substrate, magnetron sputter deposition offers the possibility to deposit thin films on heat sensitive materials such as fiber-reinforced polymers, also known as composite materials. Passive thermal probe measurements during the sputter deposition of metal layers show indeed that the temperature increase remains well below 25 °C for film thicknesses up to 600 nm. The latter thickness threshold is based on the influence of embedded metal films on the adhesion of the composite plies. Films thicker than this threshold deteriorate the mechanical integrity of the composite. The introduction of the uncured composite in the vacuum chamber strongly affects the base pressure by outgassing of impurities from the composite. The impurities affect the film properties as illustrated by their impact on the Seebeck coefficient of sputter deposited thermocouples. The restrictions to embed thin films in composites, as illustrated by both the heat flux measurements, and the study on the influence of impurities, are however not insurmountable. The possibility to use embedded thin films will be briefly demonstrated in different applications such as digital volume image correlation, thermocouples, and de-icing.

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Hsu, Cheng Hsing, His Wen Yang, and Jenn Sen Lin. "Electrical and Optical Properties of ZnO-Doped Zr_0.8Sn_0.2TiO₄ Thin Films on ITO/Glass Substrates by RF Magnetron Sputtering." Materials Science Forum 687 (June 2011): 70–74. http://dx.doi.org/10.4028/www.scientific.net/msf.687.70.

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Electrical and optical properties of 1wt% ZnO-doped (Zr0.8Sn0.2)TiO4thin films prepared by rf magnetron sputtering on ITO/Glass substrates at different rf power and substrate temperature were investigated. The surface structural and morphological characteristics analyzed by X-ray diffraction (XRD) and atomic force microscope (AFM) were found to be sensitive to the deposition conditions, such as rf power and substrate temperature. The selected-area diffraction pattern showed that the deposited films exhibited a polycrystalline microstructure. All films exhibited ZST (111) orientation perpendicular to the substrate surface and the grain size as well as the deposition rate of the film increased with the increase in both the rf power and the substrate temperature. Optical transmittance spectroscopy further revealed high transparency (over 60%) in the visible region of the spectrum.

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Silveira, B. M., J. H. Belo, R. Pinto, J. A. Silva, T. D. Ferreira, A. L. Pires, V. Chu, J. P. Conde, O. Frazão, and A. M. Pereira. "Magnetostriction in Amorphous Co66Fe34 Microcantilevers Fabricated with Hydrogenated Amorphous Silicon." EPJ Web of Conferences 233 (2020): 05003. http://dx.doi.org/10.1051/epjconf/202023305003.

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To study the magnetostriction of Co66Fe34 thin films, amorphous silicon microcantilevers were prepared by surface micromachining, and the 136 nm-thick magnetostrictive film was deposited by electron beam physical vapor deposition and patterned on top of the microcantilever structure. The magnetostriction of the Co66Fe34 films was confirmed by measuring the deflection of the cantilevers under a varying magnetic field, reaching displacements up to 8 nm. The configuration was simulated using COMSOL software, yielding a similar deflection behavior as a function of the magnetic field, with a film with a magneto strictive coefficient of λ S ~ 55 p.p.m. The experimental configuration uses a laser and a position sensitive detector to measure the displacement, based on an optical lever configuration, and a piezoelectric stage to calibrate the system.

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Li, Dan Feng, and Yan Liu. "Gas-Sensitive Behavior Based on Charge Transfer Processes of a Novel Polyoxometalate (POM)/TiO₂/SiO₂ Composite Film." Advanced Materials Research 298 (July 2011): 102–7. http://dx.doi.org/10.4028/www.scientific.net/amr.298.102.

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The POM/TiO2/SiO2 Supermolecule composite based on POM films were synthesized via an easy liquid phase deposition method (LPD) at low processing temperature for the first time and employed for studying the charge transfer processes between the film and ambient atmospheres. Here the POM is the Keggin type lacunary FeW11O399- (FeW11) polyanion. Gaseous adsorption properties of the films to noxious gases such as NH3 show that the composite is much better than that of the TiO2/SiO2 films, which may be attributed to the enhancement of the gaseous adsorption ability on the film surface as well as the modified charge transfer process between the adsorbed gases and the films due to the inducing of POM into TiO2/SiO2 matrix. In addition, more importantly, compared with the TiO2/SiO2 films, the POM/TiO2/SiO2 films showed relative faster response and recovery time at optimal working temperature of 440 K, indicating that the films have great potential to be designed as gas sensor used at low temperature.

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Kolesnikova, Evgenia A., Vladimir V. Uglov, Andrey K. Kuleshov, and Dmitry P. Rusalsky. "Formation of epitaxial InSb films on semi-insulating GaAs(100) by explosive thermal evaporation: their structure and electrical properties." Journal of the Belarusian State University. Physics, no. 3 (October 20, 2021): 20–25. http://dx.doi.org/10.33581/2520-2243-2021-3-20-25.

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In the present work, the influence of the deposition temperature of InSb films on semi-insulating GaAs(100) on their phase composition, crystal perfection and electrical properties was investigated. The InSb films of various extent of crystal perfection are formed by means of explosive thermal deposition of InSb on semi-insulating GaAs(100) substrates in the temperature range of 375–460 °C. X-ray diffraction analysis established that the films are heteroepitaxial. It is shown that an increase in the deposition temperature of InSb films from 375 to 460 °C leads to a change in the film surface roughness (Ra) from 3.4 to 19.1 nm. The Hall voltage sensitivity to the magnetic field of InSb films varies in the range of 500–1500 mV/T. The electron concentration (n) and mobility (μ) changes in the range of 2 ⋅ 1016 – 6 ⋅ 1016 cm–3, 10 ⋅ 103 – 21 ⋅ 103 cm2/(V ⋅ s). The formed InSb films on semi-insulating GaAs(100) substrate are of practical interest for the manufacture of highly sensitive miniature Hall devices.

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50

Cook, J. G., and S. R. Das. "Measurements of ion energy and flux during ion-assisted deposition of CdTe epilayers by rf magnetron-sputtering." Canadian Journal of Physics 69, no. 3-4 (March 1, 1991): 236–40. http://dx.doi.org/10.1139/p91-039.

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Previously we found that the crystallographic structure of CdTe films deposited by means of ion-assisted magnetron rf sputter deposition was very sensitive to the substrate bias voltage and temperature (S. R. Das et al. Can. J. Phys. 65, 864 (1987)). In this work, the ion energy and flux incident on the growing film were determined by means of rf-compensated Langmuir diagnostics. It was found that control of the film phase in the previous work was achieved largely by adjustments of ion energy and substrate temperature; the ion flux changed relatively little. The work is extended to a study of the discharge parameters as a function of rf power, using a CdTe target. The ion and electron densities are found to be sensitive to rf power, whereas the plasma potential Vp and the electron temperature are not. A well-known equation for Vp in terms of the positive excursions of the target voltage gives a poor estimate for Vp because of the voltage drop across the rf impedance of the target disc.

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Journal articles on the topic 'Sensitive film deposition'

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