| AVS 54th International Symposium | |
| Surface Science | Thursday Sessions |
| Session SS2-ThM |
| Session: | Surface Structure of Compound Semiconductors |
| Presenter: | D.L. Winn, University of California, San Diego |
| Authors: | D.L. Winn, University of California, San Diego J. Shen, University of California, San Diego J.B. Clemens, University of California, San Diego A.C. Kummel, University of California, San Diego |
| Correspondent: | Click to Email |
The atomic group V reconstruction of the III-V (001) surfaces have been extensively studied since these surfaces are favorable for MBE growth. The group III rich surfaces are of III-V semiconductor can be readily prepared by heating the group V rich reconstructions. The group III rich surfaces may be favorable for ALD oxides growth since they exhibit a low reactivity to O2 because the usually lack group V dimers. InAs(001) is well documented to have a (4×2) reconstruction, however, the details of the reconstruction are still under debate. Atomically resolved filled and empty state scanning tunneling microscopy (STM) images of the InAs(001)-c(8×2)/(4×2) surface reveal that the reconstruction is made up of single atom rows that run in the [110] direction which are separated by ~17 Å. In addition, atomically resolved STM images show that the row structure is most likely comprised of undimerized atoms. Cl2 was deposited onto the surface (which has been shown to preferentially react with III atoms on III-V semiconductors) to confirm that the rows were in fact comprised of In atoms. The experimental results suggest that the most probable structure for InAs(001)-c(8×2)/(4×2) is the undimerized or dimerized β3(4×2) reconstruction. The reconstruction consistent of a top layer of bicoordinated or tricoordinated In atoms at the center of the rows and tricoordinated As atoms in the second layer at the edges of the rows. Density functional theory (DFT) STM simulations were used to confirm the experimental findings. DFT reveals that the dimerized and undimerized structures are nearly degenerate consistent with STM images show the In dimerization may be temperature dependent. Both the undimerized and dimerized β3(4×2) structures lack As dimers and have a low reactivity to O2 consistent with a surface which is suitable for ALD gate oxide deposition.