Study on the introduction of Se into CdS thin films: Influence on the kinetics of the deposition and the structural and optical properties

Abstract CdS and CdS _0.75 Se _0.25 thin films were prepared at different deposition times (5-180 min) and at 75°C by chemical solution deposition. All the films are polycrystalline in nature; in the case of CdS, a mixture of cubic and hexagonal phase is present whereas the CdS _0.75 Se _0.25 films show hexagonal phase. The CdS films are dense and homogeneous with good crystalline quality and band gap (E _g ) values close to that of bulk material (2.48-2.52 eV). The properties of CdS _0.75 Se _0.25 films are mainly affected by the deposition time. The growth is slow and disordered, the crystalline quality is low, and the increase of the strain is perceivable. The E _g changes from 2.41 to 2.25 eV. Room photoluminescence has been observed in both materials. The kinetics of the growth and the consumption rate of Cd, have a similar behavior for both systems presenting a two-regime process, however, the growth rate decreases when the Se is incorporated to the chemical solution.