Technological Background and Properties of Thin Film Semiconductors

Especially with the development of nanotechnology and polymer science, interest in research and production of both efficient and lower-cost semiconductor thin film materials is increasing day by day. The use of nano-structured thin films for efficient use of solar cells in production of n-type semiconductor materials is one of the most important sources of energy and new-generation energy. Considering the indicated trends and energy requirements, it has been important to transfer this technology in detail regarding the surface technologies related to the semiconductor materials produced with thin film technologies instead of bulk materials. With this aim, this book chapter “Technological Background and Properties of Thin Film Semiconductors” includes a brief story about semiconductors, band gap theory, thin film applications, and besides traditional thin film processing methods finally a new technology called aerosol deposition technique which allows room temperature processing of several materials for semiconductor applications, respectively. It is thought that it will make important contributions to the relevant field and bring a new perspective and direct scientific research in “process-structure–property-performance” relation

In-situ formation characteristic, tribological characterization and anti-corrosion properties of quaternary composites films

Improvements of wear and corrosion properties are essential characteristic in engineering application. A study was made on the structure, electro-oxidation and properties of fabricated Z

Effect of functional composite coating developed via sulphate and chloride process parameter on the UNS G10150 steel for structural and wear mitigation in defence application

The major engineering challenge of materials in defence technologies is the vulnerability of based metals to structural and wears deformation in service. In this paper, structural formation, mechanical and thermal stability behavior of developed composite coating of Zn-30Al-7%Ti/Sn chloride bath and Zn- 30Al-7%Ti/Sn sulphate bath was investigated and compared to provide mitigation against failure. The thermal ageing property was done for 2 h at 600 �C via isothermal furnace. The structural, interfacial effect and stability behaviors of the co-deposited alloys were evaluated using scanning electron microscope equipped with energy dispersive spectrometer (SEM/EDS), atomic force microscope (AFM) and Xray diffractometer (XRD). The hardness and wear properties of the deposited coatings were examined with diamond base micro-hardness tester and reciprocating sliding tester respectively. The result shows that Zn-30Al-7%Ti/Sn sulphate co-deposition contributed to increase hardness and wear resistance than Zn-30Al-7%Ti/Sn chloride bath alloy. The stable crystal growth and significant performance of Zn-30Al- 7%Ti/Sn sulphate are link to the intermetallic phase hybrid of ZnAl, Zn4TiAl2, Zn3AlTi. Besides, it was observed that Zn-30Al-7%Ti/Sn sulphate has excellent thermomechanical stability at harsh temperature, due to the deposition of Sn/Ti on steel; leading to formation of super-hard interface. However, it was established that co-deposition of mild steel with Zn-30Al-7%Ti/Sn in sulphate bath significantly improved the structural and wear performance. It was shown that the hardness and wear of the developed composite Zn-30Al-7%Ti/Sn is increased by about 80% compared to as received sample and about 25% compared with Zn-30Al-7%Ti/Sn chloride coating developed. The improvement was proved to be an interference of zinc-composite growth. Thus, this work shows that sulphate induced Zn-30Al-7%Ti/ Sn via generation of controllable process parameter can provide significant improvements in thin filmcoating for wear mitigation and structural improvement in defence application

Multifaceted incorporation of Zn-Al2O3/Cr2O3/SiO2 nanocomposite coatings: anti-corrosion, tribological, and thermal stability

Nano-sized particle incorporation into metal matrix has gained worldwide acceptance. Al2O3, Cr2O3, and SiO2 nanoparticles have been co-deposited with Zn using electrodeposition process to produce advanced alloy. The coatings were characterized using SEM/EDX and XRD. The mechanical properties of the coatings were studied using microhardness indenter and dry abrasive wear tester. Zn-10 g/L Cr2O3 nanocomposite exhibited the highest microhardness of 228 HVN; Zn-5 g/L Al2O3 nanocomposite possessed the highest corrosion resistance and lowest wear loss. Zn-5 g/L SiO2 nanocomposite showed good stability against other composite coatings. The incorporation of the Al2O3, Cr2O3, and SiO2 shows grain refinement and modify orientation on Zn matrix

Electrical resistivity reduction and spatial homogenization of Ga-doped ZnO film by Zn layer insertion

Ga-doped ZnO (GZO) films inserted with a Zn layer were deposited at room temperature by a sputtering method to decrease carrier-compensating defects. The Zn-inserted GZO films showed a resistivity decrease resulting from an increase in carrier density. The carrier density further increased by thermal annealing and showed a maximum at around 400 degrees C. The formation of a SiO2 capping layer on the film surfaces enhanced the carrier density at temperatures higher than 400 degrees C, resulting in a lowered resistivity to 3.3 x 10(-4) Omega cm for a 200-nm-thick film. In addition, resistivity degradation that was induced at the erosion position in the sputtering deposition process disappeared. The increase in carrier density, decrease in resistivity, and homogenization of the electrical property indicate that carrier-compensating crystalline defects such as the zinc vacancy induced in Ga-doped ZnO films during the deposition process are decreased by the Zn enrichment

Degradation of contaminated industrial waste water using sol-gel derived Ru-doped TiO2 photocatalyticfilms [Sol-jel ile elde edilen Ru katki{dotless}li{dotless} TiO2 fotokatalitik filmler kullani{dotless}larak endüstriyel-kirli sularin ayriştirilmasi]

In this study, Ru-TiO2 films were deposited on glass substrates with a sol-gel route for degradation of contaminated industrial water. A solution with the Ru/Ti molar ratio of 0.05 was prepared using ruthenium and titanium based precursors. Solution characterizations were made using a turbidimeter and pH meter. The gel films, prepared by the sol-gel drop casting method, were dried at 300°C for 10 minutes and subsequently heat-treated at 500°C for 5 minutes in air. After that, the oxide thin films were annealed at 600°C for 60 minutes in air. In order to evaluate the phase structure, microstructure, optical, and photocatalytic properties of the coatings, they were investigated using XRD, SEM, and UV/Vis spectrophotometer, respectively. The obtained phase was mostly anatase TiO2. Photo-oxidation experiments were performed to obtain the photocatalytic activity of the films on impure water using an UV light source. The absorption spectrum of the water samples taken from Cigli Industrial Plant and Gediz River in Izmir/Turkey showed that they have absorbance bands in the range of 300 nm and 500 nm. The Ru doped TiO2 films exhibited highly photocatalytic activity to decompose organic species in contaminated waters. The degradation percentage ratios were calculated as 75% and 62% for two different industrial water samples

Co-deposited Zn-submicron sized Al2O3 composite coatings: Production, characterization and micromechanical properties

In this study, co-deposition of zinc (Zn)-submicron sized alumina (Al2O3) particles via electrodeposition method was investigated. Composite coatings were produced using different coating parameters such as current density, pH, temperature, agitation type, and ceramic powder content of the bath solution. Structural and microstructural properties of the coatings were characterized by X-ray diffractometer (XRD) and scanning electron microscopy with electron dispersive spectroscopy (SEM-EDS). Mechanical properties of the coatings were evaluated by dynamic ultra-micro hardness (DUH) tester, a micro-indentation technique, in detail. It was found that, co-deposition of submicron sized Al2O3 particles and Zn metal was successfully achieved via electrodeposition method without any chemical interaction between the ceramic particles and the electrolyte. Comparison of SEM images belonging to the coatings fabricated to those of the reference coatings revealed that homogenous grain structure was obtained. Finally, a boost in the micromechanical properties of the coatings was gained by changing the effective co-deposition parameters such as current density and particle content in the electrolyte. (C) 2011 Elsevier Ltd. All rights reserved

Comparison of processing parameter effects during magnetron sputtering and electrochemical anodization of TiO2 nanotubes on ITO/glass and glass substrates

Titanium thin films were deposited on glass and indium tin oxide (ITO) coated glass substrates by radio-frequency (RF) magnetron sputtering under varying sputtering parameters as: power, pressure, substrate temperature and target-substrate distance. The crystalline structure, crystallite size and texture coefficients of the films were evaluated in detail. As the evaluation points out, 100 W, 1.33 Pa ambient temperature and 70 mm were determined as the optimum sputtering parameters for intended crystalline structures. Subsequently, electrochemical anodization experiments were performed via varied electrolytes and under various anodization parameters (voltage, time and electrolyte type) in a twoelectrode electrochemical cell using the films obtained through the optimized sputtering parameters. The anodized samples were annealed at 450 degrees C for 1 h in air in order to obtain anatase transformation and the desired crystalline structure. The surface morphologies and the crystalline structures of the anodized films were evaluated through x-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. Finally, the anodization parameters for the formation of TiO2 nanotube arrays were determined as: 35 V and 35 min. in an electrolyte composed of 0.3 wt.-% NH4F - 2 wt.-% water - ethylene glycol

Comparison of processing parameter effects during magnetron sputtering and electrochemical anodization of TiO 2

Titanium thin films were deposited on glass and indium tin oxide (ITO) coated glass substrates by radio-frequency (RF) magnetron sputtering under varying sputtering parameters as: power, pressure, substrate temperature and target-substrate distance. The crystalline structure, crystallite size and texture coefficients of the films were evaluated in detail. As the evaluation points out, 100 W, 1.33 Pa ambient temperature and 70 mm were determined as the optimum sputtering parameters for intended crystalline structures. Subsequently, electrochemical anodization experiments were performed via varied electrolytes and under various anodization parameters (voltage, time and electrolyte type) in a twoelectrode electrochemical cell using the films obtained through the optimized sputtering parameters. The anodized samples were annealed at 450 degrees C for 1 h in air in order to obtain anatase transformation and the desired crystalline structure. The surface morphologies and the crystalline structures of the anodized films were evaluated through x-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. Finally, the anodization parameters for the formation of TiO2 nanotube arrays were determined as: 35 V and 35 min. in an electrolyte composed of 0.3 wt.-% NH4F - 2 wt.-% water - ethylene glycol