Photoemission study of CCl4 adsorption on Si(1 1 1)-7 × 7

Adsorption of carbon tetrachloride (CCl4) on Si(1 1 1)-7 × 7 at room temperature (RT) and low temperature (LT) was investigated by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). It was demonstrated that at RT CCl4 dissociates on the Si(1 1 1)-7 × 7 surface leaving the surface extensively adsorbed with atomic Cl species. The dissociated Cl shows site preference to Si restatoms resulting in quick extinction of dangling bonds at the Si restatoms. At LT (around 120 K), both molecular and dissociative adsorption of CCl4 occurs, which produces Cl, CClx (x ⩽ 3), and CCl4 on the surface. The dangling bonds at the restatoms and adatoms were simultaneously quenched upon the LT CCl4 adsorption. The site selectivity of restatoms to adatoms for molecule adsorption on the Si(1 1 1)-7 × 7 surface is discussed.