Papers by Keyword: Indium Oxide

Abstract: Effect of storage in air on silicon doped indium oxide (In-Si-O) thin-film transistors fabricated via solution processing has been investigated. The on/off ratio drastically increased from 10¹ just after fabrication to 10⁵ on the 10-day storage, whereas the mobility slightly decreased from 1.4 cm²/Vs to 0.38 cm²/Vs. Time constant of aging effect was 3.6 days. The behavior suggests that oxygen defects in In-Si-O films, which may be produced during thermal evaporation of Al electrodes under high vacuum, are eliminated.

Abstract: Transparent conductive films of indium oxide (In₂O₃) are deposited on a glass substrate by RF magnetron sputtering and their electrical properties are investigated in relation to their microstructure. Sputtering deposition was carried out with variations of normalized substrate temperature (T_s/T_m where T_m is the melting temperature) and argon partial pressure (P_Ar). At a very low substrate temperature (T_s/T_m < 0.1), the columnar grains with voided grain boundaries are observed in the In₂O₃ films, which are attributed to the low surface mobility and atomic shadowing effect. With an increase in the substrate temperature, tight grain boundaries are formed between the growing columnar grains. At high temperature (0.3 < T_s/T_m < 0.5), the grain surface is faceted, which is due to the high surface mobility of the sputtered atoms, and development of preferred orientation with grain growth is promoted. The growing morphology is also dependent on the argon partial pressure. At low P_Ar deposition, an inclined fibrous grain oriented to the target direction and a smooth surface structure is developed. As the P_Ar increases, a dome-shaped surface structure and columnar grains normal to the substrate are developed due to the scattering effect of the sputtered atoms. The growing morphology with substrate temperature and argon pressure coincides with the Thornton's Structure Zone Model (SZM). The lowest electrical resistivity (2.1×10^-2 Ωcm) is observed in the In₂O₃ films with tight grain boundaries and faceted grains, which corresponds to zone II region of the SZM.

Abstract: In₂O₃ nanopowder was successfully synthesized using microwave-hydrothermal method; by a very simple fast reaction between InCl₃ and urea in aqueous solution contain 1% polyethylene glycol. The products were characterized by the techniques of X-ray diffraction (XRD), Scanning electron microscope (SEM) and Fluorescent spectrum. The result shows that as-prepared In₂O₃ nanopowder is cubic phase, the morphology is square composed of many particles.

Abstract: Ultrathin indium oxide (In₂O₃) microtubes were successfully fabricated by electrospinning, magnetron sputtering and followed calcination. The hollow In₂O₃ tubes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible spectroscopy. Outer diameter of the microtubes was in the range of 700-900 nm, and inner diameter was about 400-600 nm. Optoelectronic properties of the In₂O₃ tubes were investigated by irradiation of UV light with different wavelengths (254, 308 and 365 nm). It was found that the In₂O₃ microtubes had a fast and strong response to UV irradiation.

Abstract: We report on the synthesis and photocatalytic activity of 10 wt% In₂O₃/BiOCl composite photocatalyst. The 10 wt% In₂O₃/BiOCl composite photocatalyst was synthesized by a simple chemical coprecipitation method at room temperature followed by thermal treatment at 400 °C for 2 h. During thermal treatment at 400 °C for 2 h, the amorphous-to-crystalline phase transformation occurs in In₂O₃. Pure BiOCl possesses flower-like nanostructures composed of nanoplates with single-crystal nature. With the incorporation of 10 wt% In₂O₃, the morphology of the composite photocatalyst is mainly constituted of particles with two different forms: nanoflowers of BiOCl and nanoparticles of In₂O₃. The effect of 10 wt% In₂O₃ on the photocatalytic activity of the composite photocatalyst was evaluated for the degradation of Rhodamine B (RhB) under visible light irradiation. The 10 wt% In₂O₃/BiOCl composite photocatalyst shows enhanced photocatalytic activity compared to pure BiOCl. Based on the results obtained in this study, the mechanism for the enhanced photocatalytic activity of 10 wt% In₂O₃/BiOCl composite photocatalyst is discussed.

Abstract: Various (ZnO)₅In₂O₃ ceramics were fabricated by microwave heating. Density, XRD pattern and microstructure were examined and those of Al-doped (ZnO)₅In₂O₃ were almost the same as Al-free one. Highly textured (ZnO)₅In₂O₃ ceramic was also fabricated by reactive templated grain growth (RTGG) method. The electrical conductivity was not improved by Al-doping; however it was improved slightly by microwave heating compared with conventional heating and especially improved by texturing using RTGG method. On the other hand, the absolute Seebeck coefficient in microwave heating was improved about 25% by Al-doped. Maximum electric power factor of textured specimen fabricated by RTGG method along ab-plane showed 5.76×10^-4 WK^-2m^-1 (at 873K), which was attributed to high electrical conductivity.

Abstract: The structural, electrical, and optical properties of spray deposited tin-doped indium oxide (ITO) films are reported in this work. The films have excellent properties, as a transparent and conducting electrode, for applications in a wide range of areas of optoelectronics such as photodetection and photovoltaic. One example of the ITO thin films application in semiconductor-insulating-semiconductor (SIS) efficient solar cells and modules is shown.

Abstract: Volatile Organic Compounds (VOCs) are highly reactive, often mixed with interfering gases and more importantly, their vapours in the gaseous form respond to the gas sensor devices. Oxide semiconductor based thin film gas sensors play vital role in detecting, monitoring and controlling the presence of hazardous and harmful gases in the environment at very low concentration and hence are tested for the detection of harmful or industrially important VOCs. The demand of sensitive as well stable gas/vapour sensors for direct sensing application has increased the importance of In₂O₃:SnO₂ based semiconductor materials. The paper presents the fabrication aspects of thin film gas sensors based on x1In₂O₃:x2SnO₂ compound and also their application for the detection of some important volatile organic compounds. Thin films of x1In₂O₃:x2SnO₂ were deposited using Thermal Evaporation technique and under the optimized fabrication conditions, the vapour sensors were prepared and mounted on the proper contact jig. Their response to the presence of Volatile Organic Compounds like CCl₄ was examined. The stability, the sensitivity and the response time of the sensors were studied for the different concentrations of test vapours.

Abstract: The optically transparent conducting molybdenum doped indium oxide (IMO) thin films were deposited on glass substrates by sol-gel spin coating technique. The effect of various molybdenum contents in the range of 0.25–1 at.% on the structural, morphological, optical and electrical properties was studied. XRD results confirmed the formation of cubic bixbyite structure of In2O3 with preferred orientation along (222) plane. Microstructural studies show nearly spherical morphology for thin films with size in the range of 20-40 nm. The films doped with 0.25 at.% Mo found to exhibit a minimum electrical resistivity of 188×10-3 Ω.cm and an average optical transmittance of more than 80% in the visible region with a band gap of 3.85 eV.

Abstract: Indium oxide flowerlike films were prepared on glass substrate by a simple chemical vapor deposition (CVD) coating technique. The results showed the products on the glass surface are flowerlike body centered cubic structure of In2O3 films. The flowerlike microstructures are distributed uniformly and have less overlapping, the diameters of them are about 3 µm. The deposition mechanism and the morphologies control procedure of the In2O3 were studied. As the reaction time increases, the morphologies of the microstructures were changed from cocoon-like particles to hybrid thin films, and flowerlike microstructures at last. This novel CVD method might provide a simple route for synthesizing other metal oxide or compound films.