The effect of Mn۲+ doping concentration on the optical and optoelectronicproperties of ZnS thin film

Over the years, Manganese doped Zinc sulfide thin films have gained immense attention as anion-doped semiconductors due to wide range of tunable electrical and optical properties. Thispaper concerned detailed structural, optical and electrical studies of ZnS thin film, both pure anddoped with Mn۲+ ions, successfully deposited via spray pyrolysis method on Si and glasssubstrate at different concentration of Mn ions (Mn molar fraction, x = ۰.۰, ۰.۰۵, ۰.۱, ۰.۱۵). Theeffect of various concentration of Mn ions on the morphology and optical properties of the Mndoped ZnS thin films were studied as well as electrical and photo detection characteristics wereinvestigated by analysis of as-prepared thin films’ I-V curves. Produced nanocrystalline filmswere systematically characterized by employing the following characterization techniques suchas X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet-Visible (UVVis)spectroscopy and Photoluminescence (PL) spectra measurements. The results showed thatthe Mn doping concentration can affect the microstructure, photoluminescence, absorptionspectra and hence, electrical properties of the films. XRD pattern revealed that the films are pureβ-phase. UV-Vis spectra demonstrated that absorption shoulders of the doped films were redshiftedas compared to pure ZnS owing to decrease in the energy band gap as the Mnconcentration increases. SEM showed a homogeneous morphology and dense layers. PLspectrum also exhibited an orange-red emission at ۶۳۵ (nm) due to the ۴T۱-۶A۱ transition in Mn.The PL intensity increased with increase in the Mn ions concentration. Optoelectroniccharacterizations showed that the doping of Mn ions improve the photosensivity of the ZnS basedthin films.