Effect of Zn doping on structural, morphological, optical and electrical properties of Bi2Se3 material

Abstract

In this paper, Bi2ZnxSe3-x with compositions x = 0 and x = 0.25 were synthesized using the melt technique at 850˚C. The crystal structures and surface morphologies of both the samples were investigated with X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM), respectively. XRD spectra of both the bulk alloys of Bi2ZnxSe3-x (x = 0 and x = 0.25) revealed a polycrystalline nature with a hexagonal structure. UV-Vis absorbance spectra have shown that Zn doping increases the optical band gap while decreasing the absorbance edge. The activation energy (Ea) as calculated using Arrhenius plot revealed that Zn doping in place of Se results in a decrease in Ea. The variation in resistance with temperature highlights the prevalence of phonon-phonon and electron-phonon scattering as the dominant mechanisms. Topological insulators, due to their ability to suppress intrinsic electron backscattering, are viable recommendations for use as counter electrode materials in photovoltaic cells. This approach is poised to create a novel pathway for the future commercialization of flexible photovoltaic applications.

Keywords

• X-ray diffraction
• Bismuth selenide
• Optical band gap
• Activation energy
• Electron-phonon scattering