Comparison between the effects of CdCl₂ heat treatment on CdTe films prepared by RF magnetron sputtering and close spaced sublimation methods

CdTe films were prepared on Fluorine-doped tin oxide substrate by RF magnetron sputtering and close spaced sublimation (CSS) methods, respectively. These CdTe films were then treated with a wet CdCl₂ heat process at different temperatures. The structural and optical properties of CdTe films were investigated by X-ray diffraction, scanning electron microscope and UV-Visible spectrophotometer. The results reveal that both types of CdTe films have a better crystalline and larger grain size after CdCl₂ heat treatment. However, the (422) peak has a more preferential orientation than (511) peak after CdCl₂ activation for CdTe films prepared by sputtering method, while these two peaks almost have the same intensity for CSS-prepared CdTe films. The transmittance of CdTe films prepared by CSS is apparently lower than sputtered CdTe films. Correspondingly, the efficiency of solar cells with CSS-prepared CdTe is 7.3, 2.6 % of sputtered CdTe films.