Optical and structural study of In2S3 thin films growth by co-evaporation and chemical bath deposition (CBD) on Cu3BiS3

We present the growth of In2S3 onto Cu3BiS3 layers and soda-lime glass (SLG) substrates by using chemical bath deposition (CBD) and physical co-evaporation. The results reveal that the microstructure and the optical properties of the In2S3 films are highly dependent on the growth method. X-ray diffractrograms show that In2S3 films have a higher crystallinity when growing by co-evaporation than by CBD. In2S3 thin films grown by CBD with a thickness below 170 nm have an amorphous structure however when increasing the thickness the films exhibit two diffraction peaks associated to the (1 0 3) and (1 0 7) planes of the β-In2S3 tetragonal structure. It was also found that the In2S3 films present an energy bandgap (Eg) of about 2.75 eV, regardless of the thickness of the samples.