Ab initio density functional theory study of non-polar (101{sup ¯}0), (112{sup ¯}0) and semipolar (202{sup ¯}1) GaN surfaces
The atomic structures of non-polar GaN(101{sup ¯}0), (112{sup ¯}0) and semipolar GaN(202{sup ¯}1), (202{sup ¯}1{sup ¯}) surfaces were studied using ab initio calculations within density functional theory. The bulk-like truncated (1 × 1) structure with buckled Ga-N or Ga-Ga dimers was found stable on the non-polar GaN(101{sup ¯}0) surface in agreement with previous works. Ga-N heterodimers were found energetically stable on the GaN(112{sup ¯}0)-(1 × 1) surface. The formation of vacancies and substitution site defects was found unfavorable for non-polar GaN surfaces. Semipolar GaN(202{sup ¯}1)-(1 × 1) surface unit cells consist of non-polar (101{sup ¯}0) and semipolar (101{sup ¯}1) nano-facets. The (101{sup ¯}1) nano-facets consist of two-fold coordinated atoms, which form N-N dimers within a (2 × 1) surface unit cell on a GaN(202{sup ¯}1) surface. Dimers are not formed on the GaN(202{sup ¯}1{sup ¯}) surface. The stability of the surfaces with single (101{sup ¯}0) or (101{sup ¯}1) nano-facets was analyzed. A single non-polar (101{sup ¯}0)-(1 × 1) nano-facet was found stable on the GaN(202{sup ¯}1) surface, but unstable on the GaN(202{sup ¯}1{sup ¯}) surface. A single (101{sup ¯}1) nano-facet was found unstable. Semipolar GaN surfaces with (202{sup ¯}1) and (202{sup ¯}1{sup ¯}) polarity can be stabilized with a Ga overlayer at Ga-rich experimental conditions.
- OSTI ID:
- 22304519
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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