Tin antimony sulfide (Sn6Sb10S21) thin films by heating chemically deposited Sb2S3/SnS layers: Studies on the structure and their optoelectronic properties

Tin antimony sulfide thin films (Sn6Sb10S21) were obtained on glass substrates by heating chemical bath deposited Sb2S3/SnS layers. The report primarily focuses on the structure, composition, morphology, optical and electrical properties of the thin films formed at the temperature range of 300-450 degrees C for 30 min as well as at the optimized temperature of 390 degrees C for 1, 2 and 3 h in low vacuum. X-ray diffraction and Raman analysis revealed the crystallization of ternary phase Sn6Sb10S21 at temperatures higher than 390 degrees C. X-ray photoelectron study identified the presence of Sn2+, Sb3+ and S2- states in the ternary phase and the depth profile analysis exhibited a uniform distribution of elements throughout the thickness. Further, surface morphology of the as-deposited and annealed thin films were examined using scanning electron microscopy. The optical band gaps calculated from the UV-Vis-NIR spectra were in the range of 1.26-1.45 eV with significantly high absorption coefficients (similar to 10(5) cm(-1)) which is ideal for photovoltaic conversion. Moreover, the thin films were photoconductive and when incorporated into the photovoltaic structure, Glass/FTO/CdS/ASTS/CeAg, demonstrated photovoltaic performance. The corresponding parameters V-oc, J(sc), and FF were evaluated from the J-V curves yielding the values 409 mV, 1.46 mAcm(-2) and 0.25 respectively. (C) 2020 Elsevier B.V. All rights reserved.