Structural and Electrical Properties of Cd Doped InSe Thin Films

Polycrystalline Cd doped InSe thin films were obtained by thermal co-evaporation of alpha-In2Se3 lumps and Cd onto glass substrates at a temperature of 150°C. The films were annealed at 150°C and 200°C. The films were found to contain around 46% In, 47% Se and 7% Cd in weight. The films exhibited p-type conductivity. The results of conductivity measurements have revealed that thermionic emission and variable range hopping are the two dominant conduction mechanisms, in the temperature ranges of 320-160 K and 150-40 K respectively. It was observed that above 240 K mobility is limited by the scattering at the grain boundaries. As the temperature decreases, thermal lattice scattering followed by the ionized impurity scattering dominate as the two main mechanisms controlling the mobility. Acceptor to donor concentration ratio was found to be slightly increasing due to annealing.