Effect of thickness on the microstructural, optoelectronic and morphological properties of electron beam evaporated ZnTe films

ZnTe films of different thicknesses were deposited on glass substrates at a substrate temperature of 300 oC. The thickness of the films varied in the range of 110-320 nm. The films exhibited cubic structure with preferential orientation in the (1 1 1) direction. A very high value of absorption co-efficient (104 cm-1) is observed. Band gap values in the range between 2.23 and 2.38 eV are observed when the film thickness was varied between 320 and 110 nm, respectively. The refractive index values are found to vary between 2.68 and 2.90 for the films of different thicknesses. It has been observed that the conductivity increases continuously with temperature as well as with thickness. Laser Raman spectra showed the presence of peaks at 206.8 and 411.2 cm-1corresponding to the first order and second order LO phonon of monophase ZnTe films. PL analysis confirmed the formation of monophase ZnTe films with nano grains.