SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 40: Poster: Semiconductor Substrates
O 40.2: Poster
Dienstag, 28. März 2023, 18:00–20:00, P2/EG
Assessing and processing the surface quality of free-standing wurtzite GaN in ultra-high vacuum — •Mohammadreza Rostami1, Biao Yang1, Felix Haag1, Francesco Allegretti1, Lifeng Chi2, Martin Stutzmann3, and Johannes V. Barth1 — 1Physics Department E20, Technical University of Munich, Garching, 85748, Germany — 2Institute of Functional Nano & Soft Materials, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China — 3Walter Schottky Institute and Physics Department, Technical University of Munich, 85748 Garching, Germany
Gallium nitride (GaN) is proposed as an alternative candidate to metallic substrates for assembling organic molecular structures 1. However, the formation of a persistent surface oxide layer in air considerably limits the use of GaN for well-defined interfaces 1. We have investigated n-type free-standing c-plane wurtzite GaN crystals. The effect of electron bombardment on the surface quality of free-standing GaN during ammonia annealing was studied. Surface cleaning and full removal of the oxide layer on GaN surfaces could be reproducibly achieved via sputtering and annealing cycles, leading to substantial roughening of the GaN surface. Although ammonia annealing with electron bombardment increased the N/Ga atoms ratio, the surface morphology remained rough. In addition, the on-surface chemistry of 1,3,5-Tris(4-bromophenyl) benzene (TBB) 2 was studied on the cleaned GaN surface. [1] V. Bermudez, Surf. Sci. Rep. 72 (4), 147-315 (2017) [2] M. Fritton et al. J. Am. Chem. Soc 141 (12), 4824-4832 (2019)