Influence of La3+doping on nebulizer spray pyrolysed In2S3 thin film for enhanced

In recent years, the photodetectors gained much attention due to their wide range of applications and fabrication of high-performance, cost-effective devices using environmentally friendly material is always challenging. In this work we report the fabrication of Lanthanum-doped indium sulfide thin films (In2S3:La) using a low-cost nebulizer spray pyrolysis method. La-doping concentration is varied from 0 to 5 wt% and the effect of doping on the properties of In2S3 thin films are investigated using X-ray diffraction (XRD), energy dispersive x-ray analysis (EDX), field emission scanning electron microscope (FESEM), UV-Vis spectroscopy, photoluminescence spectra. Incorporation of 3 wt% of La3+ in In2S3 lattice has substantially improved the crystallinity, surface morphology and optical properties of the thin films suitable for the device fabrication. Moderate doping of La3+ in the crystal lattice of & beta;-In2S3 led to a red-shift in the absorption edge, which benefited utilization of wider light spectrum. Photodetectors are fabricated using In2S3:La (0-5 wt%) films and photodetector performance pa-rameters are evaluated using I-V characteristics and current-time characterization. The In2S3 film with 3% La dopant concentration showed high photodetector performance with estimated detectivity (D*), photo-responsivity (R), and external quantum efficiency (EQE) of 1.11 x 1011 Jones, 5.05 x 10-1 AW-1, 118% respectively. For the same sample, the rise and fall time calculated from transient photo-response analysis is found to be 0.4 s and 0.3 s respectively. These optimally doped In2S3:La 3wt% thin film samples could be useful for the fabrication of photosensor based optoelectronic devices.

Automated summary

In this work, lanthanum-doped indium sulfide thin films (In2S3:La) were fabricated using a low-cost nebulizer spray pyrolysis method, and the effect of doping on the properties of the films was investigated. The 3% lanthanum-doped film showed improved crystallinity, surface morphology, and optical properties, making it suitable for device fabrication. The film also exhibited high photodetector performance.