Materials today communications | 2021
AgSbS2-xSex thin films: Structure, composition, morphology and photodetection properties
Abstract
Abstract Photodetectors using silver antimony seleno-sulfide (AgSbS2-xSex) thin films were fabricated and their photo sensing properties in the visible range were evaluated. The thin films were synthesized by combining chemical bath deposition and thermal evaporation techniques. The Sb2S3 thin films were deposited using chemical bath deposition followed by thermal evaporation of silver, varying the thickness from 10 to 80\u2009nm proceeded by selenization via dipping in Na2SeSO3. The thin films were fabricated as glass/Sb2S3/Ag/Se layers with different silver thickness heated at 350\u2009°C for 30\u2009min. X-ray diffraction results showed the cubic structure of AgSbS2-xSex films. Elemental analysis, chemical composition and morphological studies were done using various techniques. The optical absorption in the UV–vis-NIR region spectra of the films with varying Ag content illustrated a wide spectral range for photodetector studies. The bandgap values calculated using Tauc plot method indicated within 1.53–1.75\u2009eV, suitable for photodetector application. The current-voltage studies in the dark and illumination revealed that all the samples were photosensitive in the visible region. Methodical analysis of photoresponse was done using LEDs of various wavelengths at bias voltage of 0.5 and 1\u2009V. All the samples showed a stable and good cyclic photoresponse behavior in the wavelength region between 395–740\u2009nm. Further, the extensive photodetector application of the material was demonstrated by measuring the photoresponse using UV–vis LEDs and different laser power densities. The sensitivity and responsivity factors were calculated. With increase in Ag content, the conductivity of the films was increased and so the photocurrent response. This work asserts the application of AgSbS2-xSex thin films as a photodetector which has been explored till date for its photovoltaic properties only.