Temperature-dependent conduction and optical bandgap reduction in Zn-doped thermally evaporated Sb2Se3 thin film: a comprehensive investigation

Abstract In this manuscript, we report successful synthesis and investigation of structural, morphological, electrical, and optical properties of doped and undoped Sb2Se3. A significant enhancement in electrical and optical properties of Zn-doped Sb2Se3 is observed. The temperature dependence of direct current (dc) conductivity has been investigated in thin films of Sb2ZnxSe3-x (where x = 0 and x = 0.25) in the temperature range of 290–490 K to determine the conduction mechanism and examine the effects of doping. It shows that, in the temperature range (343–490 K), conduction is primarily due to thermally activated tunneling of charge carriers through the band tails of localized states. In the lower temperature range 293–343 K, conduction occurs via variable range hopping in the localized states near the fermi level. The decrease in the optical bandgap value as a result of Zn doping in Sb2Se3 has been correlated with the variation in density of states, increased electron–phonon interaction and steepness parameter.