Atomic and electronic structures of lattice mismatched Cu2O/TiO2 interfaces

作者：Wang Shuzhi^*; Kavaipatti Balasubramaniam; Kim Sung Joo; Pan Xiaoqing; Ramesh Ramamoorthy; Ager Joel W III; Wang Lin Wang

来源：Applied Physics Letters, 2014, 104(21): 211605.

DOI：10.1063/1.4880942

Heterojunction interfaces between metal oxides are often highly lattice mismatched. The atomic and electronic structures of such interfaces, however, are not well understood. We have synthesized Cu2O/TiO2 heterojunction thin films with 13% lattice mismatch and studied the interface via experimental methods and large-scale density function theory calculations of supercells containing similar to 1300 atoms. We find that an interface of epitaxial quality is formed via a coincidence site lattice of 8 Cu2O unit cells matching 9 TiO2 unit cells. Calculations reveal the existence of a dislocation core of the O sublattices at the interface and a random arrangement of one layer of interfacial Cu atoms. The interfacial electronic structure is found to be mostly determined by the interfacial Cu distribution, rather than by the O dislocation core. The conduction band minimum and valence band maximum states are spatially separated, and there is no strongly localized state near the core.

• 出版日期2014-5-26
• 单位Google Inc, Mountain View, CA