Chemical cleaning of oxides on GaAs (0 0 1) surface: A theoretical research

In this study, solid–liquid interaction models of 40 % HF, 40 % HCl, 40 % H2SO4, H2O on Ga2O3 and As2O3 adsorbed GaAs (0 0 1) β2(2 × 4) surface were built, using mean square displacement (MSD) results calculated by molecular dynamics methods, the cleaning ability of three solutions and water on Ga2O3 and As2O3 was researched. The co-adsorption models of solution molecules and oxides on GaAs (0 0 1) β2(2 × 4) were constructed, and the chemical cleaning mechanism was studied through the first-principles method. Electron density difference was used to analyze the charge transferring between solution molecules and oxides adsorbed surface. Valence band maximum(VBM), conduction band minimum (CBM) of the surface, highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of solution molecules and oxides were used to analyze the electron transfer mechanism. Mulliken bond population and bond length were used to analyze the desorbing ability of solution molecular.