Removal of CuS phases from electrodeposited CuInS2 films

CuS phases degrade the performance of electrodeposited and sulfurized CuInS2 films acting as absorption layers for solar cell applications. In this study, CuS phases have been effectively removed from CuInS2 films by using a two-stage thermal treatment and electrochemical etching. Multiple material analyses, including X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy, were performed to examine the presence of CuS on CuInS2 films. Results indicate that sulfurization with a two-stage thermal treatment enables sulfur atoms to distribute uniformly, thereby enhancing a full reaction between the CuIn precursor film and the sulfur powder. Additionally, electrochemical etching provides an alternative method to eliminate CuS phases in a low-temperature process.