Reactively evaporated films of indium sulphide

ß-In2S3 films are prepared by reactively evaporating indium in an atmosphere of sulphur. X-ray diffraction studies show that the grains have no preferred orientation on the substrate surface. Film properties (surface smoothness, optical transmission, and refractive index) are optimized in the substrate temperature interval (425 ± 50) K and this is explained in terms of the concept of critical optimization of Vincett. Fundamental absorption starts at (2.01 ± 0.01) eV and the transition leading to this is a direct forbidden one. Charge carriers in the film are n-type and the activation energy for electronic conduction is (0.26 ± 0.02) eV.