Band alignment of ultra-thin hetero-structure ZnO/TiO2 junction

The band alignment at the ZnO/TiO2 hetero-structure interface was measured by high resolution X-ray photoelectron spectroscopy. The valence band offset (E-ZnO - E-TiO2)(Valence) was linearly changed from 0.27 to 0.01 eV at the interface with increased ZnO coating thickness from 0.7 to 7 nm. The interface dipole presented at the ZnO/TiO2 interface was responsible for the decreased band offset. The band alignment of the ZnO/TiO2 heterojunction is a type II alignment. (C) 2013 Elsevier Ltd. All rights reserved.