Temperature-Dependent Properties of Spray-Deposited ITO Thin Films
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Sprayed indium tin oxide (ITO) thin films are synthesized by mixing adequate quantities of ethanolic solutions of indium trichloride and stannic chloride at different substrate temperatures. The pyrolytic decomposition temperature affects the properties and morphology of ITO samples. X-ray diffraction results showed that the films are polycrystalline with cubic structure and exhibit preferential orientation along (222) plane. The SEM and AFM studies indicated that the surface morphology of the samples increases with substrate temperature. The typical I500 sample is composed of cubic grains and has carrier concentration of 3.26 × 1020 cm−3 and mobility of 9.77 cm2/V s. The electrical resistivity of ITO films decreased with increasing deposition temperature. The highest figure of merit of film is 4.4 × 10−3 Ω−1. Optical absorption studies reveal that films are highly transparent in the visible region and band gap increases with substrate temperature owing to Moss-Burstein effect.
Keywordsatomic force microscopy oxides semiconducting materials x-ray diffraction
A.V. Moholkar is grateful to the Department of Science and Technology, New Delhi for awarding the BOYSCAST Fellowship (File No. SR/BY/P-02/2008) and University Grants Commission, New Delhi, India for the financial assistance through the minor research Projects No. F-47-345/2004 and No F-47-707/2008. P.S. Shinde is highly acknowledged for his efforts in improving the quality of the letters of the AFM images.
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