In situ preparation and interface characterization of TiO₂/Cu₂S heterointerface

The electronic structures and interface properties of the TiO₂/Cu₂S interface have been in situ studied after each growth step by x-ray and ultraviolet photoelectron spectroscopy. The p-doped Cu₂S films (BEVBM=0.1 eV) were grown on the highly n-doped chemical vapor deposition prepared TiO₂ (BEVBM=3.4 eV) films by thermal evaporation in a multistep growth procedure. The conduction band offset (0.7 eV), valence band offset (2.9 eV) and interface dipole (0.5 eV) were determined based on the quantitative examination of band bending occurring in the Cu2S films at higher coverage, leading to a staggered energy level configuration.