Effect of collision during vapor transport between Cd and X (X = Te2, Se2, or S2) molecules on the properties of thermally evaporated CdTe, CdSe, and CdS thin films

Abstract

In this work, CdTe, CdSe, and CdS thin films were deposited at 0°, 20°, 40°, 60° and 80° by thermal evaporation to study the effect of collision between Cd and X (X = Te2, Se2, or S2) molecules on the properties of the CdX films. Energy dispersive X-ray spectrometry analysis of the films was performed to study their elemental composition. It was observed that heavier molecules were deposited more at lower angles, while lighter molecules were deposited more at higher angles. X-ray diffraction showed that the Cd-rich films were more crystalline in nature compared to the chalcogen (Te, Se, or S) rich films. Hall effect measurements and two-probe method showed that the Cd-rich films were less resistive compared to the chalcogen (Te, Se, or S) rich films. The transmittance spectra of the films showed that the Cd-rich films had less transmittance. Current-voltage measurements showed that the nearly stoichiometric films showed better photocurrent response compared to the non-stoichiometric films. Keywords: Angular deposition, Dissociation, Collision, Hall effect, X-ray energy dispersive spectroscopy, Photocurrent