ZnO films prepared by modified sol-gel technique

Abstract

Zinc oxide films with different thicknesses have been synthesized by modified sol-gel technique. The films are polycrystalline in nature with average grain size between 32 and 57 nm. The thicker films are less strained than the thinner ones. The optical band gap of the films is ~ 3.22 eV. PL spectra are dominated by a strong luminescence peak at ~387 nm followed by a low intensity peak ~469 nm. The values of <img src='/image/spc_char/italics_e.gif' border=0><sub>∞</sup> varied between 3.58 and 4.49. The values of plasma frequency are in the range ~ 9.76-6.85x10¹⁴ s^-1. The FTIR spectra indicate the existence of the distinct characteristic absorption peak at ~475 cm^-1 for Zn-O stretching modes. The Raman spectra are dominated by the presence of a strong peak located at ~438 cm^-1 followed by peaks at ~581 cm^-1 in the higher wave number region.