Annealing and light effect on structural, optical and electrical properties of CuS, CuZnS and ZnS thin films grown by the SILAR method

Abstract

CuS, Cu 0.6Zn 0.4S and ZnS thin films were grown by successive ionic layer adsorption and reaction (SILAR) method on glass substrates at room temperature. The annealing temperature effect on the crystal structure, optical band gap and the light effect on the electrical properties of these films have been investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques were used for the investigation of structural properties of films. The SEM and XRD studies showed that the films are covered well with glass substrates and exhibit polycrystalline characterization. Using the absorption measurements, the band gap energies for CuS, Cu 0.6Zn 0.4S and ZnS thin films were found as 2.03, 2.14 and 3.92 eV at room temperature, respectively. The two-point-probe method was used for the investigation of electrical properties of films and it was found that the current increase with increasing light intensity and increasing rate in illuminated 500 W cm −2 films was greater than in others. There is an important increasing in the current values of the CuS and Cu 0.6Zn 0.4S films which have annealed at 400 °C. But the annealed ZnS thin film has less current values than the as-grown film. This is the first study which led to deposition of the CuZnS thin films by using the SILAR method.