Investigation of structural and optical properties of deposited mercury sulphide thin layers as a function of growth time

Mercury sulphide (HgS) films were deposited on glass substrates by the chemical bath deposition method (CBD) at different deposition times and then post-annealed at 300°C for about 1 h. The structure of the produced films was studied by X-ray diffraction (XRD). Elemental analyses of the prepared films were characterised by the energy-dispersive X-ray analysis (EDX). The film's optical properties were measured by spectrophotometry. The optical constants of films were derived from reflectivity curves by the Kramers–Kronig method. The absorption coefficient, extinction coefficient, refractive index, real and imaginary parts of the dielectric constant, and the optical band gaps were calculated. X-ray diffraction details showed a crystalline phase for all deposited HgS thin films with trigonal structures. Optical results exhibited photoluminescence property for HgS thin films. By increasing deposition time, the dielectric property, refractive index and band gap values are increased. The values obtained for electronic and optical properties of HgS are essentially crucial for applications in optoelectronics.