Preparation and physical properties of CuSbS2 thin films

Abstract

Copper antimony sulfide thin films were prepared by chemical bath deposition [CBD] technique at room temperature 300 K. CuSbS2 thin films attract much attention due to it is stable, non- toxic, inexpensive, has narrow band gap and has high absorption coefficient more than 105 cm-1.The structural and microstructural characterizations of the deposited and annealed films were investigated using physical methods. These include X-ray diffractometry, transmission electron microscopy and diffraction; while the elemental chemical composition of the as deposited films as well as the annealed films was examined using energy-dispersive X-ray spectrometry unites interfaced with scanning electron microscopy. The results reveal that CuSbS2 powder has orthorhombic structure and the as-deposited films are amorphous. The amorphous-to-crystalline transition was obtained by annealing the as-deposited films in argon atmosphere at 523K for 1h. X- ray diffraction and calculation of grain size of CuSbS2 thin films show that the films annealed in temperature from 523 to 673 K presents a good crystallinity and high grain size. Optical constants of all films were determined by transmission and reflection measurements in a wavelength range 400-2500 nm. The variation of the optical parameters of the prepared films, such as refractive index, extinction coefficient, absorption coefficient, and optical band gap as a function of deposition time and heat annealing temperature were determined. Two-point probe method was used for measuring the electrical resistance of the CuSbS2 films in the temperature range 303-423 K. The variation of the conductivity versus temperature exhibits two linear parts at two different temperature ranges, the first extends between 303K and 348 K, and the second between 348K and 423 K, indicating two types of conduction mechanisms through thermally activated process. The hot probe method showed that the CuSbS2 thin films exhibited P-type conductivity. CdS thin film was prepared by chemical bath deposition [CBD] technique at 353 K. The structure property of the CdS thin film was analyzed by X-ray diffraction (XRD), transmission electron microscope (TEM) and electron diffraction (ED). The energy-dispersive X-ray spectrometry techniques, (EDX),employed for investigated the elemental chemical composition of the deposited films. Spectrophotometric measurements (in the wavelength range from 400 nm to 2500 nm) have been made in order to determine the optical constants. Theelectrical properties for CdS thin film were also measured.The [FTO/ CdS/ CuSbS2/Ag] solar cell have been the fabricated by the chemical bath deposition technique.The [FTO / CdS/ CuSbS2/ different metal electrode] solar cellshave been the fabricated by thermal evaporation technique. The [Al/ Si (n-type)/ CuSbS2/ different metal electrode]solar cellshave been the fabricated by thermal evaporation technique.TheI-V characteristics of the solar cells under dark and illumination have been studied. The effect of changing the metal electrode on the efficiency of solar cells has been studied. Keywords Copper antimony sulfide; chemical bath deposition [CBD] technique; X-Ray Diffraction (XRD);Scanning Electron Microscopy (SEM); Transmission Electron Microscopy (TEM); Differential Thermal analysis (DTA); Optical properties; Electrical Properties; solar cells; current-voltage characteristics.