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 °C with substrate temperature of 400 °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 1×106 Ω cm.