| AVS 54th International Symposium | |
| Surface Science | Thursday Sessions |
| Session SS2-ThM |
| Session: | Surface Structure of Compound Semiconductors |
| Presenter: | T. Song, University of California, San Diego |
| Authors: | T. Song, University of California, San Diego D.L. Winn, University of California, San Diego J. Shen, University of California, San Diego A.C. Kummel, University of California, San Diego |
| Correspondent: | Click to Email |
The group-V (As or Sb) rich reconstructions of III-V semiconductors have been extensively investigated since these surfaces are favorable for MBE growth. However, the group-III (Ga or In) rich reconstructions can readily be prepared by heating the group-V rich reconstructions, and the group-III rich reconstructions may be favorable for ALD gate oxide deposition due to their low reactivity to oxygen. Although the group-III rich surfaces have several potential applications, many III-V semiconductors, including InGaAs, have unidentified group-III rich reconstructions. Four different group-III rich 4x2 reconstructions of In0.5Ga0.5As(001)-(4×2) were modeled using DFT: ζ (4×2), β2(4×2), β3(4×2), and the undimerized β3(4×2) structures. Multiple polymorphs (Ga and In positions) were investigated. The undimerized β3(4×2) reconstruction most closely matches the experimental room temperature STM images of In0.53Ga0.47As/InP(001)-c(8×2)/(4×2). This reconstruction consists of a top row of undimerized In/Ga atoms which are bonded to tri-coordinated As atoms. In the undimerized β3(4×2) structure, the row In/Ga atoms are sp hybridized. Conversely, in the dimerized β3(4×2) reconstruction, the top row In/Ga atoms are sp2 hybridized. DFT calculations showed that the undimerized β3(4×2) reconstructions are more stable in energy. The density of states (DOS) of the β3(4×2) reconstructions showed that the undimerized β3(4×2) structure had a band gap while the dimerized β3(4×2) structure was metallic. The correlation between hybridization and electronic structure is due to the influence of hybridation and bonding structure on the filling of the dangling bonds.