Structural, morphological, optical and electrical properties of CdTe films deposited by CSS under an argon-oxygen mixture and vacuum

CdTe thin films were deposited by CSS at a pressure of 1 mbar, under different mixtures of argon and oxygen and in vacuum, on glass substrates. The samples were prepared under three source-substrate temperature conditions. The films were characterized by X-ray diffraction, UV-vis spectroscopy, SEM and two-probe resistivity. XRD patterns indicated that the films grown at low oxygen content and source temperature of 550 degrees C with substrate temperature of 400 degrees C showed a high preferential orientation in the (1 1 1) plane. The crystalline grain size was between 31 and 40 nm. The films had a direct band gap in the range 1.44-1.49 eV. SEM images showed higher aggregate sizes for the films deposited at higher temperatures and grain size decreases as oxygen content increases. The resistivity of the films was around 1 x 10(6) Omega cm. (C) 2010 Elsevier B.V. All rights reserved.