Preparation and characterization of Sb 2 (S x Se 1− x ) 3 thin films deposited by pulsed laser deposition

Antimony sulfide-selenide, Sb 2 (S x Se 1− x ) 3 (0 < x < 1), with a tunable bandgap combining the advantages of antimony sulfide (Sb 2 S 3 ) and antimony selenide (Sb 2 Se 3 ), shows great potential as a promising light-absorbing material in low-cost, low-toxic, and high-stability thin-film solar cells. In this work, high-quality Sb 2 (S x Se 1− x ) 3 thin films were successfully prepared by pulsed laser deposition (PLD) using the Sb 2 (S x Se 1− x ) 3 compound targets for the first time and realized tunable bandgaps by simply changing the S/(Se + S) ratios of compound targets. The effects of substrate temperature and S/(S + Se) ratio on the structural, morphological, and optical properties of films were investigated separately. It was discovered that 500 °C was the optimum substrate temperature to grow high-crystallinity, good-morphology, and low-defects Sb 2 (S x Se 1− x ) 3 thin films, and the film with S/(S + Se) ratio of 0.2 showed optimal properties. Optical characterization demonstrated all Sb 2 (S x Se 1− x ) 3 thin films owned high absorption coefficients above 10 5 cm −1 at the visible light region and suitable bandgaps near the ideal value of the Shockley–Queisser limit. The results of energy dispersive spectrometer showed that all films were poor in Sb and rich in (S + Se), which was a favorable condition for them as light absorbers. The activation energy obtained from the electrical measurement revealed that the conductivity of Sb 2 (S x Se 1− x ) 3 thin films was mainly contributed by the intrinsic thermal excitation at 350–500 K. Our research offered a simple and reliable technology to prepare Sb 2 (S x Se 1− x ) 3 thin films with adjustable bandgaps and favorable properties, which is expected to promote the development and application of this semiconducting material in thin-film solar cells.