Deposition of Ga and As Adatoms on the Ge (111) and Si (111) Surfaces: A First-Principles Study

摘要

The (1x1) and ( sq root 3 x sq root ) R30 deg (T4) structures of Ga and As adatoms on the Ge(111) and Si(111) surface are studied using the firstprinciples calculations. The surface energetics predicts, in some cases, a transformation of the T4 structure (surface covered with 1/3 monolayer (ML) of adatoms) into domains of the 1-ML covered (1X1) structure and areas of clean reconstructed surface. For As adatoms, such phase separation is favored on both substrates, while for Ga adatoms, it is only preferred on the Ge(111) surfaces. These results are compared with experimental observations.