Effect of annealing on the AC conductivity and the dielectric properties of In2Te3 thin films

In2Te3 thin films were prepared by thermal evaporation technique. The composition of the films is checked by energy dispersive X-ray analysis. X-ray analysis showed that the as-deposited In2Te3 films as well as films annealed at temperatures less than or equal to 473 K have crystalline structure. The ac conductivity sigma (ac)(omega), the dielectric constant epsilon (1) and the dielectric loss epsilon (2) of In2Te3 films were studied in the temperature range 303-373 K and in the frequency range 100 Hz-100 kHz. The ac conduction activation energy DeltaE(sigma)(omega) was found to be 0.065 eV for the as-deposited films. The ac conductivity was found to obey the relation sigma (ac)(omega) = A omega (s), where a is the frequency exponent. The obtained temperature dependence of s is reasonably interpreted by quantum mechanical tunneling model. Both the dielectric constant epsilon (1) and the dielectric loss epsilon (2) increased with temperature and decreased with frequency in the investigated range. The frequency and temperature dependencies of sigma (ac)(omega), epsilon (1), and epsilon (2) for the annealed samples have the same behavior as that for the as-deposited samples. However, values of sigma (ac) (omega), epsilon (1), and epsilon (2) measured at any frequency and temperature increased with annealing temperature up to 473 K. It was found also that DeltaE(sigma)(omega) decreased with annealing temperature.