Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5360741 | Applied Surface Science | 2008 | 5 Pages |
Abstract
Surface phase diagram of recently proposed GaAs(0 0 1)-(2 Ã 4)γ is systematically investigated by using our ab initio-based approach. We focus on the (4 Ã 7) domain consisting of c(4 Ã 4)-like and (2 Ã 4)-like regions to clarify surface dimer constituents as functions of temperature T and As (As2 and As4) pressure pAs by comparing chemical potentials of surface dimers in the vapor phase with that on the surface. The calculated results under As4 imply that Ga dimers in the c(4 Ã 4)-like region tend to become stable with increase of temperature and appear at the conventional growth condition such as T â¼Â 800 K and pAs â¼Â 10â6 Torr, while the (2 Ã 4)-like region favors As dimers. This is consistent with temperature dependence of change in surface dimer constituents on the c(4 Ã 4) and (2 Ã 4)β2 clarified in our previous study. Furthermore, the surface phase transition from the c(4 Ã 4) to (2 Ã 4)β2 via (2 Ã 4)γ is discussed on the basis of the phase diagram obtained in this study.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Tomonori Ito, Toru Akiyama, Kohji Nakamura,