Fabrication of visible light photodetector using co-evaporated Indium Sulfide thin films

Indium Sulfide (In2S3) is a promising candidate to replace Cadmium Sulfide (CdS) as a buffer layer in thin film solar cells because of its n-type conductivity and wide energy band gap. In this study, In2S3 thin films are deposited on glass substrates at different substrate temperatures in the range of 200-350 degrees C by co-evaporation technique. The X-ray diffraction and Raman analysis confirm the formation of tetragonal beta-In2S3 thin films. The X-ray Photoelectron Spectroscopy and Energy Dispersive X-ray Spectroscopy results reveal presence of constituent elements. The energy band gap was observed in the range of 2.45-2.54 eV and band gap is increasing with increase of substrate temperature. Hall Effect measurement shows n-type conductivity for all films. Photodetectors were fabricated and tested under the light illumination by solar simulator with AM 1.5G filter. The photo detection parameters like sensitivity, responsivity and detectivity were calculated for all photodetectors.