Role of Mo-doping concentration on In2S3 thin film for photodetecting application by nebulizer spray pyrolysis method

This research report presents the photosensing behavior of the indium sulfide thin films with concentration of molybdenum (Mo) doping (0, 1, 2 and 3%), developed using the nebulizer-aided spray pyrolysis method. Due to the influence of varied Mo contents on their growth, crystallinity, morphology, distribution of elemental composition, optical and photosensing behavior of these formed films were all carefully investigated. Examining the X-ray diffraction patterns reveals that the produced films have a cubic phase, with a preference for orientation along the (400) plane. The presence of nano-grains with dot-like particles was evidenced using the morphological analysis of all the films. In addition, the energy gap values of In2S3 were reduced from 2.87 to 2.80 eV, while ultraviolet (UV) absorption was increased. Three emission peaks were visible in the films' photoluminescence (PL) spectra at 415, 479, and 523 nm. The resulting Mo-doped In2S3 films demonstrated outstanding UV photo-response and photoelectrical properties with voltage at 5 V. The maximal response (R) (7.52 × 10–1 A/W), detectivity (D*) (4.53 × 1010 Jones), external quantum efficiency (EQE) (243%), and rapid photoswitching speed were found for 2% Mo-doped In2S3 thin film. This report also verified the UV photosensing properties were considerably altered by selecting dopants with suitable doses.