Dielectric and conduction studies on hot-wall deposited CdSe films

CdSe films are deposited using hot-wall deposition technique on glass and ITO substrates. From the XRD analysis, the structural parameters like crystallite size, dislocation density and strain were calculated. Films had preferential orientation along (0 0 2) and the structure of the film corresponded to wurtzite nature. From the EDAX analysis a slight increase in the cadmium content is observed as thickness increases. The dielectric study has been carried out on the stoichiometric films at different frequencies and temperatures to study their effect on capacitance, dielectric constant and dielectric loss. To explore the effect of illumination on these fundamental dielectric parameters, measurements are taken in dark as well as under an illumination of 1000 lx. and observed slight variation in these parameters. The temperature coefficient of capacitance, relative permittivity and linear expansion coefficient are evaluated. From the AC conduction studies the conduction was found to be due to hopping. Variation of conductivity with temperature reveals the presence of two activation energies. The Mott–Schottky plot for the films yields the value for carrier concentration in the range 1017–1018 cm−3 and the conduction was found to be n-type.