Electrical conductivity, structure and hall effect measurements of InSe films

Abstract

Stoichiometric InSe films were prepared by discrete evaporation using spectrally pure (99.999%) InSe powder in a residual pressure of about 4×10 −6 Torr. The thickness of the films was varied from 500 to 3000 Å. The elctrical conductivity of the films was measured by Van der Pauw's method. The as-deposited films had an amorphous structure as observed with an electron microscope. Thermal annealing was carried out through a number of annealing cycles and a transformation to a crystalline state during the process was evidenced by the electron micrographs. Conductivity measurements were made on the amorphous films from the transition temperature to liquid air temperature and the activation energies were calculated from the variation in conductivity with temperature. The density of states at the Fermi level was also calculated at low temperatures. Hall effect measurements were made on the annealed films and the Hall mobility μ H, the Hall coefficient R H and the carrier concentration n were evaluated.