Preparation and characterization of nanostructures of in-doped ZnO films deposited by chemically spray pyrolysis: Effect of substrate temperatures

Abstract

We deposited undoped (ZnO) and indium-doped ZnO (IZO) films onto glass substrate via ultrasonic spray pyrolysis technique. The variation in structural, surface morphology, electrical, optical and photoluminescent properties as a function of substrate temperature is investigated. X-rays pattern confirms that as-synthesized IZO phase is grown along a (002) preferential plane. Nanosized grains (<50 nm) are determined by X-ray analysis. Morphology of as-grown films shows broadened nanostructures which have grown along c-axis and nanostructures are found to be smooth (RMS similar to 60 nm). Study by spectrophotometer reveals that the asgrown films are highly transparent in the visible and IR spectra (T similar to 88%), and that the bandgap is slightly narrowed (3.17 eV). Electrical measurements confirm the enhancement of conductivity, rho<1 Omega cm, due to indium incorporation into the starting solution. An electron concentration of 10(17) cm(-3) and a mobility of 3 cm(2)/Vs are found for IZO films grown at 400 degrees C. The photoluminescence analysis demonstrates strong yellow (2.1 eV) and blue (2.8 eV) light and weak green (2.3 eV) emissions. (C) 2013 Elsevier Ltd. All rights reserved.