Preparation of high-sensitivity In2S3/Si heterojunction photodetector by chemical spray pyrolysis

High photosensitivity n-In2S3/p-Si heterojunction photodetectors were made by depositing indium sulfide In2S3 thin film on a p-type silicon substrate using chemical spray pyrolysis with molarity of 0.1 and 0.2 M at 400 degrees C. Characterization techniques of X-ray diffraction XRD, scanning electron microscopy SEM, energy dispersive X-ray EDX, atomic force microscopy AFM, UV-Vis spectrophotometer, and Hall measurements were utilized to investigate structural, optical and electrical properties of the films. XRD investigation revealed polycrystalline grown films. EDX analysis showed good stoichiometry synthesized films with [S]/[In] ratios of 1.04 and 1.08 for In2S3 films prepared with 0.1 and 0.2 M respectively. Optical energy gap of the films decreased from 2.87 to 2.7 eV after increasing film morality from 0.15 to 0.2 M. Photo-response investigation of photodetector prepared with 0.2 M showed two peaks of response located at 400 and 750 nm with photosensitivity of 0.5 and 0.68 A W-1 respectively. Pulsed responsivity of photodetectors at 365 nm was found to be 200 mV W-1 at 0.1 M and 250 mV W-1 at 0.2 M.