Computational simulation of threshold displacement energies of GaAs
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Efrain Hernandez-Rivera Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109, USA; and WMRD, US Army Research Laboratory, APG, MD 21005, USA
Danhong Huang and Paul D. LeVan US Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, NM 87117, USA
Fei Gaoa) Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109, USA (Received 8 December 2016; accepted 20 January 2017)
Classical molecular dynamics (MD), along with a bond-order potential for GaAs, has been used to study threshold displacement energies (Ed) of Ga and As recoils. Considering the crystallographic symmetry of GaAs, recoil events are confined in four unit stereographic triangles. To investigate the displacement energy’s dependence on crystallographic orientation, more than 3600 recoil events were simulated to uniformly sample values of Ed. Various defect configurations produced at these low energy recoils and the separation distances of Frenkel pairs were quantified and outlined. For both Ga and As, the minimum, Edmin , is found to be 8 eV, but the maxima, Edmax , are 22 and 28 eV for Ga and As, respectively. The distribution of Ed within unit stereographic triangles indicates that Ed shows a weak dependence on the recoil directions, in contrast to other semiconductors. The average threshold displacement energy is 13 6 1 eV, which is in excellent agreement with available experiments.
I. INTRODUCTION
Semiconductor compounds from the III–V direct band gap family have been extensively studied for the last decades due to their wide range of applications, such as space electronic components,1 replacement of silicon in microelectronic components,2,3 and solar cells.4,5 Gallium arsenide (GaAs) has been shown to have superior electronic properties to conventional semiconductors, leading to a large body of research to advance its properties. For instance, GaAs has higher saturated electron velocity and higher electron mobility so as to develop extremely high performance highelectron-mobility-transistors (HEMTs).6 For these compelling reasons, GaAs has been proposed as one of the better alternatives for space-based electronics application,7 but its properties can be altered due to the bombardment of high energy ions from space environment. When accounting for space radiation damage, the GaAs crystal lattice may be heavily damaged by Contributing Editor: Susan B. Sinnott a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2017.46
energetic recoils, and atoms are displaced from their lattice sites, resulting in the performance degradation of electronic devices. Therefore, understanding radiation damage mechanisms in GaAs is essential to mitigate radiation induced effects to within acceptable ranges.8–11 However, often fundamental concepts and/or parameters are overlooked or not properly analyzed. To theoretically estimate the total damage in materials, one of the crucial parameters associated with pri
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