Preparation and characterization of Bi-doped antimony selenide thin films by electrodeposition

Bi-doped antimony selenide (Sb_2−xBi_xSe₃) thin films have been prepared by potentiostatical electrodeposition and post annealing treatment. Cyclic voltammetry (CV) was used to investigate the electrochemical behaviors of electrodeposition. The suitable deposition potential for film preparation was determined to be about −0.40 V vs. SCE combining with CV, energy dispersive X-ray spectroscopy (EDS), environmental scanning electron microscope (ESEM) studies. After annealing, film shows improved crystallinity and a basic orthorhombic Sb₂Se₃ structure but having a larger d-spacing due to the substitution of Bi for Sb in Sb₂Se₃ lattice. The annealed film exhibits an absorption coefficient of larger than 10⁵ cm⁻¹ in the visible region, an direct optical band gap of 1.12 ± 0.01 eV, the n-type conductivity, an carrier concentration of 1.1 × 10¹⁹ cm⁻³ and an flat band potential of −0.40 ± 0.03 V vs. SCE.