Polycrystalline thin films of antimony selenide via chemical bath deposition and post deposition treatments

摘要

We report a method for obtaining thin films of polycrystalline antimony selenide via chemical bath deposition followed by heating the thin films at 573 K. in selenium vapor. The thin films deposited from chemical baths containing one or more soluble complexes of antimony, and selenosulfate initially did not show X-ray diffraction (XRD) patterns corresponding to crystalline antimony selenide. Composition of the films, studied by energy dispersive X-ray analyses indicated selenium deficiency. Heating these films in presence of selenium vapor at 573 K under nitrogen (2000 mTorr) resulted in an enrichment of Se in the films. XRD peaks of such films matched Sb_2Se_3. Evaluation of band gap from optical spectra of such films shows absorption due to indirect transition occurring in the range of 1-1.2 eV. The films are photosensitive, with dark conductivity of about 2× 10~(-8) (Ω cm)~(-1) and photoconductivity, about 10~(-6) (Ω cm)~(-1) under tungsten halogen lamp illumination with intensity of 700 W m~(-2). An estimate for the mobility life time product for the film is 4× 10~(-9) cm~2 V~(-1).