Journal of Non-Oxide Glasses Vol. 2, No 4, 2010, p. 175 - 182 PREPARATION AND CHARACTERIZATION OF MERCURY CADMIUM SULPHIDE THIN FILMS M.A. ELERUJA a , A.V. ADEDEJI a , B. OLOFINJANA a , O. O. AKINWUNMI a , I.A.O. OJO b , G.O. EGHAREVBA b , O. OSASONA c , E.O.B. AJAYI a* a Department of Physics, Obafemi Awolowo University, Ile-Ife b Department of Chemistry, Obafemi Awolowo University, Ile-Ife c Department of Electronic and Electrical Engineering, Obafemi Awolowo University, Ile-Ife 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. (Received December 1, 2010; accepted December 13, 2010) Keywords: Cd-Hg ; thin films; MOCVD technique, XRD 1. Introduction CdS and various II-VI semiconductor compounds have been studied in various forms including thin films. The interest in this class of materials is because of their emission which covers the technologically attractive blue and green spectra regions [1]. In particular, more attention is focused on CdS thin films because their expected gap emission lies close to the highest sensitivity of the human eye. CdS thin films are versatile materials which are useful in electronic devices like field effect transistor, optical windows for solar cells [2], photovoltaic technology and optoelectronic devices such as thin film optical integrated circuits [3]. The use of CdS thin film as heterojunction window layer in the fabrication of semiconductor solar cells has also been reported [4]. Lately, the thin film of CdS solar cell has been considered to be promising alternative to more widely used silicon devices [5]. While CdS thin film is versatile, the appearance of pin holes in the structure, the degeneration of the material and the lattice mismatch are its major disadvantages [6]. HgS thin films have not been widely studied in the past because of the difficulties involved in their preparation [7]. However, the compound is now gaining more attention. Patil et al. [8], in their work deposited HgS thin films that exhibited cubic phase with optical band gap of 2.0 eV with n-type conductivity. β-HgS thin films have been found to be photoactive with p-type electrical conductivity [9] and show a blue shift in the band gap with a band gap of 0.54 eV [10]. A search for alternate window materials is in two folds, one is the search for a completely new material and the other is the addition of different elements to already known materials such as CdS, CdTe, ZnS, etc. This addition leads to the formation of miscible system such as Zn x Cd 1-x S, * Corresponding author email: eajayi@oauife.edu.ng