STRUCTURAL-ANALYSIS OF DOMAIN BOUNDARIES ON SI(111)7X7 SURFACES BY SCANNING TUNNELING MICROSCOPE

The scanning tunneling microscope has been used to study domain boundaries on Si(111)7 × 7 surfaces. Several kinds of regular defect structures along the domain boundaries on Si(111)7 × 7 surfaces have been observed with atom resolution. By combining with the dimer-adatom-stacking fault model, their detailed atom structural models are given. It is found that there are three important factors that determine the boundary structure. The most important factor is the strong interaction between dimer and adatom. The next one, in some cases, is the difference between the faulted half and the unfaulted half. Additionally, the metastable (2n + 1) × (2n + 1) triangle subunit structure such as the 5 × 5 triangle subunit may play an important role in determining the defect structure along the domain boundary in some cases.