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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Enhanced Photoconductivity of SIGE-Trilayer Stack by Retrenching Annealing Conditions
摘要： We studied the effect of short term furnace annealing over the photoconductive properties of tristacked layer i.e. TiO2/(SiGe/TiO2)3. The structure was prepared by depositing alternate layers of TiO2 and SiGe films, using sputtering technique. A direct-current magnetron transmission electron microscopy and grazing incidence spectroscopy was used to analyze the morphology of the structure. Photoconductive properties were studied by measuring photocurrent spectra at different applied voltages and temperatures. Tristack layers were obtained with 5-10 nm SiGe nanocrystals (NCs) by annealing at 600 °C for 5 min. No sign of SiO2 formation was found inside stacked layers. A maximum in the photocurrent spectra was observed at 994 nm at 300 K but it red-shifted gradually to 1045 nm with decrease in temperature to 100 K. This transition in peak maxima is attributed to SiGe NCs, due to lattice vibration and to contribution of non-radiative recombination at low temperatures.
关键词： TiO2,magnetron sputtering,nanocrystals,photoconductivity,SiGe,annealing
更新于2025-09-23 15:22:29
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Nickel Doping on Cobalt Oxide Thin Film Using by Sputtering Process-a Route for Surface Modification for p-type Metal Oxide Gas Sensors
摘要： This study proposes a route for surface modification for p-type cobalt oxide-based gas sensors. We deposit a thin layer of Ni on the Co oxide film by sputtering process and annealed at 350 °C for 15 min in air, which changes a typical sputtered film surface into one interlaced with a high density of hemispherical nanoparticles. Our in-depth materials characterization using transmission electron microscopy discloses that the microstructure evolution is the result of an extensive inter-diffusion of Co and Ni, and that the nanoparticles are nickel oxide dissolving some Co. Sensor performance measurement unfolds that the surface modification results in a significant sensitivity enhancement, nearly 200% increase for toluene (at 250 °C) and CO (at 200 °C) gases in comparison with the undoped samples.
关键词： Toluene,Co oxide thin film,Ni-doped,Gas sensor,RF sputtering,CO
更新于2025-09-23 15:22:29
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Gas Breakdown and Discharge Formation in High-Power Impulse Magnetron Sputtering
摘要： Discharge behaviors of high-power impulse magnetron sputtering with different targets have been investigated. Distinct current–voltage curves and target current waveforms are observed. Breakdown voltage and the maximum target current show a periodic drop with the increase of atomic number in subgroups and periods. The target current density is found to be mainly affected by the secondary electron emission yield. Thus, its magnitude is unable to directly evaluate the ionization degree of sputtered atoms in high-power impulse magnetron sputtering (HiPIMS) process. In this paper, the interactive influence of secondary electron emission, sputter yield, and ionization energy on the ionization degree of sputtered atoms is discussed based on the analysis of the voltage and current characteristics. As a result, targets can be categorized into three sorts according to the ionization degree: 1) low ionization degree targets, such as Ag and C less than 10%; 2) intermediate ionization degree targets like Cr and Cu with 55% and 35%; 3) Ti, Zr, and Mo targets with the second ionization processes. These results provide institutive operation ranges for the state-of-the-art HiPIMS applications.
关键词： optical emission spectroscopy (OES),ionization degree,Current waveform,gas breakdown,high-power impulse magnetron sputtering (HiPIMS)
更新于2025-09-23 15:22:29
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Highly-transparent, UV-B protective Al-Zn-O films with potential application in greenhouse screen systems
摘要： Extremely thin, Al-Zn-O composite films (21±6 nm) are deposited on fused silica substrates under various percentages of oxygen in the oxygen/argon gas mixture (3, 4.5, 6, and 7.5 %). The films are prepared by a cylindrical DC magnetron sputtering system, utilizing a single compound target. The effects of the oxygen percentage on the compositional, morphological, and optical properties of the films are investigated by energy-dispersive X-ray spectroscopy, scanning electron microscopy, UV-Visible spectrophotometry, and atomic force microscopy. The chemical composition of the films is Al1 Z1+X O with 0.2<X<1. The average visible transmittance of 93.6% with a high level of uniformity is obtained when the sputtering deposition performs under the oxygen percentage of 6%. It is found that the optical band gap of the films can be tailored towards higher energy by increasing oxygen percentage; however, the adjustable range is not so significant. The results offer cost-efficient films with high, uniform transmittance in the visible region and with an ability to attenuate more than 10% of incident UV-B radiation (280-315 nm). This type of films can potentially be included in greenhouse screen systems to effectively protect the plants from the elevated UV-B radiation without altering natural conditions.
关键词： Al-Zn-O film,cylindrical DC magnetron sputtering,band gap tailoring,effective UV-B protection of plants
更新于2025-09-23 15:22:29
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Spectroscopic Studies of Magnetron Sputtering Plasma Discharge in Cu/O2/Ar Mixture for Copper Oxide Thin Film Fabrication
摘要： Magnetron sputtering plasma for the deposition of copper oxide thin film has been investigated using optical emission spectroscopy and Langmuir probe. The intensity of the light emission from atoms and radicals in the plasma were measured using optical emission spectroscopy (OES). Then, Langmuir probe was employed to estimate the plasma density, electron temperature and ion flux. In present studies, reactive copper sputtering plasmas were produced at different oxygen flow rate of 0, 4, 8 and 16 sccm. The size of copper target was 3 inches. The dissipation rf power, Ar flow rate and working pressure were fixed at 400 W, 50 sccm and 22.5 mTorr, respectively. Since the substrate bias plays an important role to the thin film formation, the substrate bias voltages of 0, -40, -60 and -100 V were studied. Based on OES results, oxygen emission increased drastically when the oxygen flow rate above 8 sccm. On the other hand, copper and argon emission decreased gradually. In addition, Langmuir probe results showed a different ion flux when substrate bias voltage was applied. Based on these plasma diagnostic results, it has been concluded that the optimized parameter to produce copper oxide thin film are between -40 to -60 V of substrate bias voltage and between 8 to 12 sccm of oxygen flow rate.
关键词： optical emission spectroscopy,Langmuir probe,thin film,magnetron sputtering,Copper oxide
更新于2025-09-23 15:22:29
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ZnO-based nanocomposites prepared by a vapor phase route, investigated by XPS
摘要： Nanostructured materials based on ZnO, eventually functionalized with titanium oxide (TiO2) or tungsten oxide (WO3), were fabricated on fluorine-doped tin oxide-coated glass substrates by a combined chemical vapor deposition/radio frequency-sputtering route. In particular, the present work focuses on the use of x-ray photoelectron and x-ray excited Auger electron spectroscopies for a detailed investigation of the system O 1s, Zn 2p3/2, Zn 3p, and Zn LMM core levels, as well as Ti 2p and W 4f photoelectron peaks. In a nutshell, the results of these analyses highlight the obtainment of pure ZnO nanodeposits, as well as of ZnO-TiO2 and ZnO-WO3 composites, in which the identity of each component is preserved, and the occurrence of an electronic interplay between ZnO and WO3 phases in the latter system.
关键词： RF-sputtering,CVD,x-ray photoelectron spectroscopy,WO3,TiO2,ZnO
更新于2025-09-23 15:22:29
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Detection of NH<SUB>3</SUB> Using ZnO Thin Film Sensor Deposited on Si/SiO<SUB>2</SUB> Substrate Derived by RF Magnetron Sputtering
摘要： This paper reports the research results of Zinc Oxide (ZnO) thin film gas sensor which is able to detect low concentration of ammonia gas (NH3). Pure ZnO layer is deposited on Si/SiO2 substrate at room temperature by RF magnetron sputtering technique. Pt micro-heater, platinum resistance thermometer (PRT) and gold electrodes are also fabricated along with ZnO thin film to make a complete NH3 sensor device and the fabrication process is discussed in detail in this manuscript. The deposited ZnO thin film is annealed at different temperatures and the effect of annealing temperature on the properties of ZnO thin film is analyzed by using various characterization techniques such as surface profilometer, XRD, SEM, EDX, etc. A measurement set-up is established for the measurements of various sensor parameters. An operating temperature is optimized for the NH3 gas sensor to enhance the sensitivity of the device. The optimized operating temperature is achieved and measured by Pt heater and PRT, respectively. The measurements are also performed for Pt micro-heater and PRT to calibrate the temperature with respect to heater current. Finally, the gas sensing measurements are performed in the range of small NH3 concentration (below 10 ppm) and the results confirm very good sensitivity even in very small NH3 concentration.
关键词： NH3 Gas,Thin Film,Pt Microheater,NH3 Gas Sensor,RF Sputtering,ZnO
更新于2025-09-23 15:22:29
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Effect of substrate temperature on structural and thermoelectric properties of RF-magnetron sputtered SnSe thin film
摘要： SnSe is a potential thermoelectric material, but there are few reports about the thermoelectric properties of the film. In this work, SnSe thin films were deposited on glass substrates by RF magnetron sputtering from SnSe alloy target. The effect of substrate temperature on the structural and thermoelectric properties was investigated. It was found that the columnar grains and the surface roughness of the films increase with increasing the substrate temperature. The film deposited at 558 K exhibited a high crystalline quality and stoichiometric composition, which has a maximum power factor of 1.4 uWcm-1K-2 at 575 K. The results of this work demonstrate the importance of high substrate temperature to obtain high thermoelectric performance SnSe films.
关键词： SnSe thin film,sputtering,thermoelectric properties
更新于2025-09-23 15:22:29
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A promising CuOx/WO3 p-n heterojunction thin-film photocathode fabricated by magnetron reactive sputtering
摘要： A CuOx/WO3 thin-film based on p-n heterojunction proposed as a highly performance and stable photocathode. The CuOx/WO3 thin-film was deposited by magnetron reactive sputtering layer by layer, followed with slow rate annealing in O2 ambient. This is an excellent method for high-quality and uniform composite thin-film deposition with large areas at a high growth rate. The optimized CuOx/WO3 thin-film photocathode after slow rate annealing at 500 °C in O2 provides an obviously enhanced photoinduced current density of -3.8 mA cm-2 at a bias potential of -0.5 V (vs. Ag/AgCl), which value is 1.5 times higher than that of bared CuOx thin-film. This highly enhanced photoelectrochemical performance is attributed to p-n heterojunction, which accelerates the photogenerated electrons and holes transfer to n-WO3 and p-CuOx, thereby accelerate the separation of photogenerated carries. In addition, WO3 layer covered on the surface of CuOx thin film can improve the stability of Cu2O in electrolytes.
关键词： p-n heterojunction,Tungsten oxide,Photoelectrochemical,Copper oxide,Magnetron reactive sputtering
更新于2025-09-23 15:22:29
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Fabrication, Modelling and Assessment of Hybrid 1-D Elastic Fabry Perot Microcavity for Mechanical Sensing Applications
摘要： 1-D multilayer dielectric films consisting of seven pairs of SiO2 and TiO2 alternating layers are deposited on a SiO2 substrate using the radio frequency sputtering technique. The thicknesses of the film layers are chosen to reflect the visible radiation around 650 nm. An elastic microcavity layer made of Polydimethylsiloxane was sandwiched between two Bragg reflectors. A fabrication process was then developed for elastic microcavity in order to tailor the thickness, establish the surface planarity and to increase reproducibility of the samples. Optical transmittance of the single Bragg reflector and the microcavity were both simulated and measured. A comparison between measurement data and Transfer Matrix Method calculations shows a favourable correlation. Furthermore, in order to assess the suitability of the microcavity as a force sensor, transmittance measurements were carried out as a function of the applied forces. The change in the elastic microcavity thickness due to applied forces resulted in cavity resonance peak shifts proportional to the applied forces.
关键词： Optical Characterization and Modelling,Silica and Titania,1D Elastic Photonic Crystal,Mechanical Sensor,RF sputtering,PDMS
更新于2025-09-23 15:22:29