| AVS 54th International Symposium | |
| Surface Science | Thursday Sessions |
| Session SS-ThP |
| Session: | Surface Science Poster Session |
| Presenter: | H. Kim, Chonbuk National University, Korea |
| Authors: | H. Kim, Chonbuk National University, Korea H. Li, Chonbuk National University, Korea G. Duvjir, Chonbuk National University, Korea J.M. Seo, Chonbuk National University, Korea |
| Correspondent: | Click to Email |
From STM/STS studies of the reconstructed Si(5 5 12)-2x1 surface, it has been found that its atomic structure of the unit-cell consists of four kinds of 1-D structures: honeycomb(H) chain, π-bonded chain, dimer-adatom(D/A) row, and tetramer(T) row. One (5 5 12) period is composed of three subunits, (337) unit with a D/A row [D(337)], (337) unit with a T row [T(337)], and (225) unit with both a D/A and a T row. Two kinds of adjacent subunits, T(337)/D(337) and D(337)/(225), are divided by H chains, while one kind of adjacent subunits, T(337)/(225), is divided by a π-chain. Existence of two chain structures has been confirmed as follows: (1)In the empty-state topographic image, H-chain has 2x periodicity along the chain due to buckling, while π-chain with missing atom defects has 1x periodicity. (2)From local STS measurement, the empty-state onset of π-chain is 0.5 eV smaller than that of H chain. (3)Exposed benzene molecule adsorbs selectively on π-chain. (4)In the homoepitaxy on Si(5 5 12)-2x1 at 550C, the first chain grown on D/A row is π-chain. Two chain structures commute with each other depending upon the external stresses perpendicular to the chain, which is the same for two row structures, D/A and T rows. These results indicate that, although numbers of consisting atoms and dangling bonds(DBs) of two different chains are identical, different DB directions induced by tensile stresses perpendicular to the chain result in such a distinct reactivity.