Preparation and characterization of mercury cadmium sulphide thin films
The precursor bis-(morpholinodithioato-s,s')-Cd-Hg was prepared and the thin films of mercury cadmium sulphide were deposited on sodalime glass substrate by Metallorganic Chemical Vapour Deposition (MOCVD) technique. The surface morphology was obtained using Stereoscan 430i LEICA Scanning Electron Microscope. The elemental analysis was carried out using Energy Disperse X-ray (EDX). The ratio of the elements in the prepared films obtained from the EDX was found to be Hg:Cd:S = 17.55:38.12:44.32, giving a stoichiometry of Hg x Cd (1-x) S (1-δ) , δ = 0.20. . A direct band gap of 2.36 eV was obtained from the analysis of the absorption spectrum. Electrical characterization was carried out both in the dark and normal room illumination. The dark and room illumination conductivities were found to be of the same order (10 -6 Ω -1 cm -1) and the activation energy for both conditions are 0.12 eV and 0.19 eV respectively. The conductivity type was found to be p-type using the hot probe method.