Theoretical investigation of an intermediate in the STM tip-induced atomic process on H/Si(100) surfaces

摘要

STM tip-induced atomic process on hydrogenated Si(100) surfaces [H/Si(100)] has been explored for decades of years. The surface atomic processes at low sample bias voltages where direct electronic excitation from σ→σ~* is inaccessible had been attributed to multiple-vibrational excitation induced by inelastic tunneling electrons from STM tip. However, some experimental observations cannot be fully explained by the multiple-vibrational excitation theory. In this paper, we proposed reaction mechanisms to explain the surface atomic processes occurred on different H/Si(100) surfaces, based on our theoretical calculations. The proposed reaction mechanisms revealed a common hydrogen bridged intermediate on different H/Si(100) surfaces and such intermediate could explain the experimental observation of single dangling bonds which had been previously ascribed to Si-H bond broken induced by multiple-vibrational excitation. Moreover, some experimental observations, such as site selectivity, temperature, and isotope effect can be well explained by the mechanisms.