Opto-electrical characterization of γ-In2Se2.5Te0.5thin layers☆1

The synthesis of single-phase γ-In2Se2.5Te0.5 alloy thin films with low substitution of selenium by tellurium was carried out by a direct method from In and (Se1−xTex) thermal evaporation and a subsequent heat treatment. A correlation between the film properties and alloy composition was observed. These γ-In2Se2.5Te0.5 films changed from p-type conduction to n-type by the addition of Te, and showed a high optical absorption coefficient (α > 104 cm−1) and an energy gap of about 1.45 eV, narrower that of γ-In2Se3 thin films. An improvement of the electronic transport properties, i.e., the carrier concentration and mobility, was achieved as proved by electrical conductivity and Hall measurements.