GaAs(001)表面薄膜成長初期過程の量子論的シミュレーション

抄録

Computer-aided simulation is one of ideal vehicles for the study of dynamic growth process in thin film formation. The initial growth process of GaAs thin films is theoretically investigated from a viewpoint of quantum mechanics using Monte Carlo simulation. An ab initio-based Monte Carlo simulation study implies that Ga adatom migration behavior on the GaAs(001)-(2×4)β1 surface strongly depends on the adatom coverage. This can be successfully interpreted by the electron counting model. Based on this finding, newly developed electron counting Monte Carlo method is applied to the surface structural change during adatom impingements. The GaAs(001)-(2×4) surface changes its structure from initial (2×4)β2 to another electronically stable (2×4)β1 via (2×4)α. The Ga adsorption of 0.5 monolayer on the GaAs(001)-c(4×4) surface induces As desorption to form (2×4)-like structure with As coverage θ_AS=0.75. These results qualitatively consistent with experimental results suggest that quantum mechanical contribution is essential to thin film growth process of compound semiconductors.