EFFECT OF ANNEALING ON THE ELECTRICAL-PROPERTIES OF IN2SE3 THIN-FILMS

Thin film samples of In2Se3 were prepared from synthesized polycrystalline In2Se3 by a thermal evaporation technique. X-ray analysis show that the synthesized material has alpha-phase structure, while the as-deposited films have an amorphous structure. The films have beta-phase structure after annealing at temperature greater than or equal to 523 K. The conduction activation energy (E(sigma)) of the as-deposited samples, as obtained from the temperature dependence of the electrical conductivity, is 0.391 eV. The obtained value of E(sigma) was explained according to a previously postulated band structure of the investigated material. The electrical conductivity of the investigated samples behaves differently with time after annealing at different elevated temperatures. On one hand, E(sigma) decreased for samples after annealing at 423 and 473 K to 0.313 and 0.262 eV respectively; this may be due to the increase of the degree of ordering in the investigated compound with annealing. On the other hand, E(sigma) increased for samples after annealing at 523 K to 0.787 eV; this is due to its crystallization to the beta-phase, as confirmed by its X-ray diffraction pattern.