Electrodeposition and ab Initio Studies of Metastable Orthorhombic Bi2Se3: A Novel Semiconductor with Bandgap for Photovoltaic Applications

A metastable phase of Bi2Se3 with orthorhombic structure has been obtained by potentiostatic electrodeposition onto Si(100) substrate. The ideal stoichiometry and single orthorhombic phase could be obtained only within a restricted potential window, where mutual underpotential co-deposition is assumed to occur. Optical and electrical Characterization indicates a bandgap of 1.25 eV, close to the maximum efficiency in the Shockley Queisser limit, and n-type semiconducting behavior with moderate electrical resistivity. Theoretical calculations using density functional theory were used to support the structural and optical results. Due to the favorable set of properties with respect to isomorphic compounds such as Bi2S3, Sb2S3, and Sb2Se3, this material could lead to efficient and low-cost new thin film-based photovoltaic devices.