The significance of in situ conditions in the characterization of GaSb nanopatterned surfaces via ion beam sputtering

Osman El-Atwani, Birck Nanotechnology Center, Purdue University
Jean Paul, Birck Nanotechnology Center, Purdue University
Alex Cimaroli, Purdue University
Anastassiya Suslova, Purdue University
Sami Ortoleva, Purdue University

Date of this Version



Journal of Applied Physics: Volume 110, Issue 7


Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics: Volume 110, Issue 7 and may be found at The following article has been submitted to/accepted by Journal of Applied Physics. Copyright (2011) Osman El-Atwani, J. P. Allain, Alex Cimaroli, Anastassiya Suslova, and Sami Ortoleva. This article is distributed under a Creative Commons Attribution 3.0 Unported License.


A systematic study is conducted in order to elucidate the underlying mechanism(s) for nanopatterning with low-energy irradiation of GaSb (100) under normal incidence. Ion energies between 50 and 1000 eV of Ar+ and ion fluences of up to 10(18) cm(-2) were employed. Characterization of the shallow (e.g., 1 to 6 nm) amorphous phase region induced by irradiation and the subsurface crystalline phase region is accomplished with low-energy ion scattering spectroscopy and x-ray photoelectron spectroscopy, respectively. In situ studies are conducted due to the strong chemical affinity for oxygen of GaSb. The studies conclude that at energies below 200 eV, the native oxide layer hampers nanopatterning until it becomes removed at a fluence of approximately 5 x 10(16) cm(-2). At this energy and threshold fluence, the surface is enriched with Ga atoms during irradiation. At energies above 200 eV, the native oxide layer is efficiently removed in the early irradiation stages, and thus the detrimental effects from the oxide on nanopatterning are negligible. In situ surface concentration quantification indicates that the surface enrichment with Sb atoms in the amorphous phase layer increases with the incident ion energy. Post-air exposure characterization reveals that the measured enrichment of the surface with gallium is due to oxygen reduction by Ga atoms segregated from both the amorphous and the crystalline phase regions as a result of air exposure. (C) 2011 American Institute of Physics. [doi:10.1063/1.3642997]


Nanoscience and Nanotechnology