Growth of multilayer Bi₂Se₃-Sb₂Se₃ thin films by SILAR technique

Abstract

The successive ionic layer adsorption and reaction (SILAR) technique is well suited for producing large area thin films, as they are required in solar energy related applications. It is applied for the growth of multilayer Bi₂Se₃-Sb₂Se₃ thin films onto glass substrates. The preparative parameters are optimized to get multimonolayers of Bi₂Se₃-Sb₂Se₃ of terminal

thickness ~ 0.185 μm. Structure, surface morphology, optical band gaps and electrical resistivity of the Bi₂Se₃-Sb₂Se₃ thin films are studied. Structural study by X-ray diffraction shows that multilayer Bi₂Se₃-Sb₂Se₃ thin film formation is possible by SILAR technique. Scanning electron microscopy and atomic force microscopy studies show that films formed are nanocrystalline. The optical band gap was estimated to be 1.57 eV using optical absorption studies, which lies between the individual band gaps of Bi₂Se₃ and Sb₂Se₃. The dark electrical resistivity is found to be of the order of 10⁵ Ω-cm.