Nitrogen Adatom Diffusion on a Ga-Rich GaN (0001) Surface
DAI Xian-Qi1,2, WU Hua-Sheng2, XIE Mao-Hai2, XU Shi-Hong2, TONG Shuk-Yin3
1Department of Physics, Henan Normal University, Xinxiang 453002
2Department of Physics, The University of Hong Kong, Hong Kong
3Department of Physics and Materials Science, City University of Hong Kong, Hong Kong
Nitrogen Adatom Diffusion on a Ga-Rich GaN (0001) Surface
DAI Xian-Qi1,2;WU Hua-Sheng2;XIE Mao-Hai2;XU Shi-Hong2;TONG Shuk-Yin3
1Department of Physics, Henan Normal University, Xinxiang 453002
2Department of Physics, The University of Hong Kong, Hong Kong
3Department of Physics and Materials Science, City University of Hong Kong, Hong Kong
Abstract： The diffusion of N adatoms on a Ga-rich GaN(0001) surface has been studied using density-functional theory. The configuration of Ga adatoms on a Ga-rich GaN surface has been identified. The first adlayer Ga adatoms are on top of the terminating substrate Ga atoms, and the outmost adlayer Ga adatoms exist randomly at the T4 or H3 sites. A very different diffusivity of N adatoms on a Ga-rich GaN(0001) surface has been found. The excess Ga adatoms on a GaN(0001) surface reduce the diffusion barrier by 0.75 eV and influence the migration path. It seems that bilayer Ga adatoms are helpful for N atom diffusion.
2004, Vol. 21 
