Temperature Dependent Structural and Optical Properties of Nanostructured Cr Doped CdO Thin Films Prepared by DC Reactive Magnetron Sputtering

摘要

Nanostructured Cr doped CdO thin films were deposited by DC reactive magnetron sputtering technique on glass substrates at different substrate temperatures. The structural, electrical and optical properties of Cr doped CdO films were investigated. From XRD data, all the films are highly oriented in the (2 0 0) direction. Surface morphology of the samples has been studied using FESEM and the elemental composition of the films is determined from EDS spectra. The minimum resistivity of 1.92 x 10"4 ii.cm is obtained for the thin film deposited at substrate temperature of 350 °C. The optical transmittance of Cr doped CdO thin films increases with the increase of substrate temperature from room temperature to 350 °C. The optical absorption edge of the films is shifted towards lower wavelengths with increase in the substrate temperature. The optical direct band gap values of Cr doped CdO films increased with the increase of substrate temperature. The increase in optical band gap may be due to improvement in crystallinity of the films and Burstein-Moss shift.