Computational Investigation of Coverage-Dependent Behavior on Functionalization of the Semiconductor X (100)-2 x 1 Surface (X = C, Si, and Ge) by Cycloaddition of Transition Metal Oxides

摘要

By means of density functional theory in conjunction with periodic slab models, coverage-dependent behavior for chemical functionalization of the semiconductor X (100) (X = C, Si, and Ge) surface by traditional cycloaddition of transition metal oxides (OsO4 and RuO4) has been investigated. We found that the transition-metal-mediated oxygen transfer reaction for cycloaddition of OsO4 and RuO4 onto X (100) is quite favorable. The adsorption energies decrease as the coverage is increased, and the band gap is widened or reduced depending on both the type of model molecules and the coverage. Furthermore, it is feasible to form organic layer films of transition metal oxides onto the semiconductor X (100) surface as reflected by the high adsorption energies at the saturated coverage, which could lead to new hybrid multifunctional materials. In addition, interestingly, two distinct and competitive monolayer structures are simultaneously observed on both the Si (100) and the Ge (100) surfaces, but only one stable monolayer geometry is found on the C (100) surface, indicating the flexibility of controlling the self-assembled molecular binding configuration using transition metal oxides on the semiconductor X (100) surface. It is hoped that our results may help to seek appropriate chemical modification methods to widen the application fields of the group IV semiconductor-based hybrid materials.