Investigations on Physical Properties of Nanostructured Cr Doped CdO Thin Films for Optoelectronic Applications

Cr doped CdO thin films were deposited on glass substrates by DC reactive magnetron sputtering method by varying oxygen flow rates from 1 to 4 sccm. XRD spectra shows that the films exhibit a simple cubic crystal structure with preferred orientation along (111) direction. FESEM images of Cr doped CdO thin films exhibits columnar structure and the grain width decreases with the increase of oxygen flow rate. Atomic force microscopy was used to examine the surface topography of the films. The average roughness and rms roughness for Cr doped CdO thin film deposited at oxygen flow rate of 2 sccm are 3.28 nm and 5.47 nm. The four-probe method was employed to determine the electrical resistivity of the films. The minimum resistivity of 4.47 x 10-4 Ω.cm, high optical transmittance of 90% and carrier concentration of 1.36 x 1020 cm-3 are obtained for Cr doped CdO thin film deposited at oxygen flow rate of 2 sccm.