Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.30: Poster

Montag, 23. März 2009, 14:30–17:00, P2

Novel Low Temperature Surface Reconstructions of GaN(0001) Surface — Danda Acharya, •Kendal Clark, Muhammad Haider, Erdung Lu, Arthur Smith, and Saw-Wai Hla — Ohio University, Physics and Astronomy Department, Athens, Ohio 45701, USA.

Low temperature electronic and structural properties of a nitrogen polar, gallium rich GaN (0001) surface have been investigated by using scanning tunneling microscopy and spectroscopy at 5 K and 80 K substrate temperatures. Deviating from the known room temperature surface reconstructions, we find novel low temperature surface structures having a rhombohedral lattice with a 12 * 12 gallium atomic periodicity. From the tunneling spectroscopy data, two of the surface states of GaN (0001) originated from the overlap of gallium adatom wavefunctions have been directly observed. By means of bias dependent scanning tunneling microscope imaging, we show that these novel surface structures are contributed from the predicted surface state bands, B1 and B2. This work is supported by the National Science Foundation NSF-PIRE grant, OISE 0730257, and the United States Department of Energy, DE-FG02-02ER46012 grant.