Confirmation of intrinsic electron gap states at nonpolar GaN(1-100) surfaces combining photoelectron and surface optical spectroscopy

Journal Article · Mon Apr 28 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4873376· OSTI ID:22267740

Eisenhardt, A.; Shokhovets, S.; Krischok, S. ^[1]; Räthel, J.; Speiser, E.; Neumann, M. D.; Navarro-Quezada, A.; Esser, N. ^[2]

---

1. Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau (Germany)
2. Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Albert-Einstein-Strasse 9, 12489 Berlin (Germany)

The electronic structure of GaN(1–100) surfaces is investigated in-situ by photoelectron spectroscopy (PES) and reflection anisotropy spectroscopy (RAS). Occupied surface states 3.1 eV below the Fermi energy are observed by PES, accompanied by surface optical transitions found in RAS around 3.3 eV, i.e., below the bulk band gap. These results indicate that the GaN(1–100) surface band gap is smaller than the bulk one due to the existence of intra-gap states, in agreement with density functional theory calculations. Furthermore, the experiments demonstrate that RAS can be applied for optical surface studies of anisotropic crystals.

• OSTI ID: 22267740
• Journal Information: Applied Physics Letters, Vol. 104, Issue 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALS
DENSITY FUNCTIONAL METHOD
ELECTRONIC STRUCTURE
GALLIUM NITRIDES
PHOTOELECTRON SPECTROSCOPY
SURFACES