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O: Fachverband Oberflächenphysik

O 74: Poster Metal and Semiconductor Substrates: Structure, Epitaxy and Growth

O 74.4: Poster

Mittwoch, 19. März 2025, 18:00–20:00, P2

Band alignment at InP/TiO₂ interfaces from density-functional theory — Isaac Azahel Ruiz Alvarado¹, Christian Dressler², and •Wolf Gero Schmidt¹ — ¹Universität Paderborn, Germany — ²TU Ilmenau, Germany

The natural band alignments between indium phosphide and the titanium dioxide polymorphs rutile, anatase and brookite as well as amorphous titania are calculated from the branch point energies of the respective materials. Type-I alignment is predicted, irrespective of the type of titania interfacing with InP. The actual band offset may differ, however, from the natural band alignment depending on the microscopic structure of the interface. Supercell calculations are performed for the interface between P-rich InP(001) surface and amorphous titania thin films. The valence band offset increases substantially compared to the natural band alignment, while the conduction band offset is reduced, resulting in nearly aligned conduction bands. Depending on the interface properties, both type-I and type-II interfaces are observed in the simulations. The results show that with careful control of the microscopic interface structure and the atomic order of the titania film a very wide range of band alignments becomes accessible.

Keywords: InP; TiO2; interface; band alignment; DFT