Effect of annealing temperature on SnS thin films for photodetector applications

• Published in: Journal of materials science. Materials in electronics Vol. 33; no. 8; pp. 4794 - 4805
• Main Authors: Alagarasan, Devarajan, Hegde, S. S., Varadharajaperumal, S., Arun Kumar, K. Deva, Naik, R., Panjalingam, Sathiya Priya, Massoud, Ehab El Sayed, Ganesan, R.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2022; Springer Nature B.V
• Subjects: Absorptivity; Annealing; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystallites; Materials Science; Morphology; Optical and Electronic Materials; Optical properties; Photometers; Quantum efficiency; Room temperature; Thin films
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-07668-7

Tin sulfide (SnS) thin films were deposited at room temperature (RT) by thermal evaporation method and subsequently annealed at 150–350 °C in N 2 atmosphere. The influence of annealing temperature on composition, structural, morphological and optical properties of the thin films has been investigated. X-ray diffraction (XRD) analysis and Raman studies confirmed the formation of single phase SnS films at RT and annealed up to 300 °C. The crystallite size increased from 24 nm for as-deposited film to 37 nm for the 300 °C annealed film and further reduced to 18 nm for the 350 °C annealed film. The film annealed at 200 °C was found to have better morphological features with (111) preferred oriented crystallites. The absorption coefficient, optical band gap ( E g ) of the deposited films were estimated from the optical transmittance measurements. Photodetectors are fabricated by depositing Ag contacts on SnS thin films using a metal mask and photo response was tested under dark and illumination conditions using 532 nm laser of varying power intensities. The photodetectors performance is evaluated using responsivity ( R ), external quantum efficiency (EQE), and specific detectivity ( D *). The specific detectivity of 6.8 × 10 10 Jones obtained in the present study is nearly two orders of magnitude greater than that reported earlier.