Structural and Optical Properties of the New Absorber Cu_2ZnSnS_4 Thin Films Grown by Vacuum Evaporation Method

摘要

This work studies dependences of structural and optical properties on the substrate temperature of Cu_2ZnSnS_4 thin films deposited onto glass substrates by thermal evaporation method. The thicknesses of the films were in the range 500-600 nm. Their structure and composition are studied by X-ray diffraction, scanning electron microscopy, dispersive X-ray spectroscopy, optical reflectance and transmittance measurements. The variations of the Microstructural parameters, such as crystallite size(L), dislocation density(δ), stacking fault probability (α) and strain(ε), with substrate temperature were investigated. The results show the crystallite sizes increaser as the substrate temperature increases. The variation of the dislocation density and the stacking fault probabilities and strain decrease as the substrate temperature increases. Optical measurements show that all the CZTS thin films have relatively high absorption coefficient between 10~4 and 10~5 cm~(-1) with p-type conductivity.