Electrical properties of amorphous Ge26InxSe74-x chalcogenide thin films

Abstract

Amorphous Ge26InxSe74-x (1 ≤ × ≤ 5) chalcogenide thin films have been deposited by thermal evaporation technique. The temperature-dependence of DC conductivity and the temperature and frequency dependence of AC conductivity have been studied in the temperature range 295–523 K and in the frequency range 4–8 MHz. The study of the temperature-dependent of DC conductivity refers to the presence of two distinct conduction mechanisms; the activation energies for each were calculated and it was observed that their values decrease by increasing In content. Besides, in the low-temperature region, the variation of the conductivity against temperature was further analyzed according to the variable-range hopping model based on Mott’s relation, whereby the hopping parameters were evaluated. For all investigated compositions, the variation of the AC conductivity against frequency at the studied temperatures was interpreted according to the correlated barrier hopping (CBH) model which based on Jonscher’s power law, whereby the potential barrier height, WM, and the theoretical optical bandgap, Eg, were calculated.