Optical investigation of tin telluride (snte) thin films grown at different deposition voltage

Abstract

Thin films of tin telluride (SnTe) were successfully deposited on fluorine doped tin oxide (FTO) conducting glass substrates by means of the electrochemical deposition technique. The films were prepared over a duration of 10 seconds at four distinct voltages (10 V, 11 V, 12 V, and 13V). Optical characterization was carried out using a UV 1800 spectrophotometer across a wavelength range of 200 nm to 1000 nm. Although maximum optical absorption was recorded in the ultraviolet region for all films, the results indicate that the deposition voltage exerts a non
uniform influence on the optical behaviour of the grown SnTe thin films. The film deposited at 11 V demonstrated the most favourable
performance, yielding the lowest optical band gap of 1.41 eV and the highest optical conductivity of approximately 2.64 × 10−3
S/cm. Films grown at 10 V, 12 V, and 13 V exhibited high transparency in the visible and near infrared regions, whereas the 11 V sample showed markedly lower transmittance. Reflectivity across all samples was generally low, with the 11 V film recording the least reflectance over all measured wavelengths. Band gap energies ranged from 1.41 eV to 1.90 eV, signifying considerable tunability of the optical properties through voltage adjustment. Additional optical parameters, including absorption coefficient, extinction coefficient, and refractive index, were evaluated and discussed. The results suggest that the 11 V SnTe thin film is a promising candidate for the absorber layer in photovoltaic cells, while the
remaining films show potential for various optoelectronic applications requiring high optical transparency.