Photo sensing characteristics of Ag doped Sn2S3 thin films grown by economic nebulizer spray pyrolysis technique

Polycrystalline films of pure and Ag-doped (1, 2, 3, 4, and 5 wt%) tin trisulfide (Sn2S3) thin films were synthesized using an affordable nebulizer-assisted spray pyrolysis technique for use in light-detecting devices. The Xray diffraction analysis revealed that all samples displayed crystallization in the orthorhombic crystal structure. Images obtained with the Field Emission Scanning Electron Microscope showed that the grains in the film exhibited spherical morphology. Doping silver into the Sn2S3 lattice up to 3 wt% led to a decrease in its band gap, with a subsequent rise observed for excess Ag beyond 3 %. According to photo-sensing analysis, the sensing properties of Sn2S3 thin films with Ag doping was found to increase up to 3 % and then a decrease was observed for further addition of Ag. The Sn2S3:3% Ag composite demonstrated superior levels of responsivity (R), external quantum efficiency (EQE), and detectivity (D*) with values of 19.5 x 10-2A/W, 45 %, and 45.8 x 109 Jones, respectively. The enhanced photo-detection capability was attributed to the enhanced carrier generation rate and the controlled modulation of grain size. The Sn2S3 thin film sample doped with 3 wt% of Ag displayed a highest photocurrent than the pristine sample. Thus doping of Ag into Sn2S3 was found to improve its photocurrentgenerating capability, making it an attractive option for photo sensor applications.