Studies on structural, optical, and photoelectric properties of CdS sub(1-x)Se sub(x) films fabricated by selenization of chemical bath deposited CdS films

In this paper, high-photosensitive CdS sub(1-x)Se sub(x) films are synthesized by a two-step technique, which includes the chemical bath deposition of CdS films and a following selenization process. The structural, optical, and photoelectric properties of the CdS sub(1-x)Se sub(x) films were investigated. With the substitution of selenium for sulfur atoms, grain sizes of the as-prepared CdS sub(1-x)Se sub(x) films are effectively enlarged and reach the scales of the films thickness when the selenization temperature exceeds 450 degree C. With increasing the selenization temperature from 350 to 550 degree C, the band gaps of CdS sub(1-x)Se sub(x) films gradually decrease from 2.37 to 1.82eV. Under the co-action of the grain-size enlargement and band-gap decrease, the CdS sub(1-x)Se sub(x) films fabricated at 450 degree C show very pronounced photosensitivity. Noteworthy, the ratio of photo to dark conductivity of the CdS sub(1-x)Se sub(x) film selenized at 450 degree C reaches 1.110 super(5), suggesting a promising application potential in the photoelectric devices.