Identification of the Si 2p surface core level shifts on the Sb/Si(001)-(2 × 1) interface

We investigated the effect of Sb-dimer-induced Si(001) relaxation on the Si 2p core level by high-resolution photoemission spectroscopy. Two surface components, S* and C*, were identified in the Si 2p core level measured on the Sb/Si(001)-(2 × 1) surface at 1 monolayer Sb coverage. By using the Sb-Ge site exchange process, a Ge layer was inserted between the Sb dimers and the Si substrate to separate the Si 2p contribution arising from different atomic layers. We demonstrated that S* includes the contribution of the first, second, and third layers, whereas only the third layer contributes to C*.