Nanocrystalline ZnxTe100−x (x = 0, 5, 20, 30, 40, 50) thin films: Structural, optical and electrical properties

In the present paper, the structural, optical and electrical properties of nanocrystalline ZnxTe100−x (x = 0, 5, 20, 30, 40, 50) thin films (average thickness ~ 350 nm), deposited by thermal evaporation, have been studied. The X-ray diffraction results revealed that single phase ZnxTe100−x was obtained at x = 50. Fourier transform infrared spectra also revealed the formation of zinc blende phase at x = 50. Energy dispersive X-ray spectroscopy confirms the elemental composition. Field emission scanning electron micrographs confirmed the uniform deposition of all thin films. UV-Vis-NIR results revealed that the optical band gap, calculated by Tauc's plots, increases with increase in Zn content. This may be due to the alloying effect. Temperature dependent dark conductivity showed that conductivity is thermally activated process having single activation energy in the measured temperature range (300-375 K). The dark conductivity and activation energy decreased with increase in Zn content. The explanations of variation in the properties of ZnTe with increase in Zn percentage have been provided.