Study on physical properties of indium-doped zinc oxide deposited by spray pyrolysis technique

Transparent conducting indium doped zinc oxide (IZO) thin films have been deposited on soda-lime glass substrates by the spray pyrolysis technique. The structural, electrical, and optical properties of these films were investigated as a function of substrate temperature. In this work the substrate temperature was varied between 350 degrees C and 500 degrees C. X-ray diffraction pattern reveals that at 350 degrees C dominant peak is (100) orientation. By increasing substrate temperature from 350 degrees C to 450 degrees C, sheet resistance decreases, from 302 Omega/square to 26 Omega/square, then at 500 C increases to 34 Omega/square. In the useful range for deposition (i. e. 450 C to 500 C), the orientation of the films was predominantly (002). The lowest sheet resistance (26 Omega/square) is obtained at substrate temperature of about 450 degrees C with the transmittance of about 75%. Study of scanning electron microscopy images shows that films deposited at 400 degrees C, have grain size as large as 574 nm, while with increasing substrate temperature to 450 degrees C, grain size becomes smaller and reaches to a value of about 100 nm with spherical shape. At 500 degrees C grain size value would be around 70 nm with the same spherical shape. (C) 2011 Elsevier B. V. All rights reserved.