Characterization of CuInSe2 thin films grown by photo-assisted electrodeposition

Abstract

A photo-assisted one-step electrodeposition has been applied to help in forming smooth and dense CuInSe2 (CIS) films. The difference in surface morphology and crystalline quality between CIS films with and without photo-assistance has been investigated. In the photo-assisted electrodeposition process, a halogen lamp providing maximum light intensity at about 0.6μm–1.0μm was used as light source to be irradiated onto the surface of Mo-coated soda lime glass substrates. Electrodeposited CIS thin films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and Raman spectroscopy. SEM and AFM results show a smoother film with lower roughness by photo-assisted electrodeposition at lower deposition potential. From the XRD patterns, it was found that photo-assistance enhanced the crystalline quality, and the enhancement remained after annealing at 500°C for 120s. The analysis of Raman spectra indicated a reduction in secondary phases after applying photo-assistance. These results suggested effects of photo-assistance including activating surface diffusion and growing high-crystalline quality films with reduced defects during electrodeposition.