Comparative photoemission study of low-pressure hydrogen, silane, and disilane adsorption on Si(111)7×7

We present an in situ study of low-pressure hydrogen, silane, and disilane chemisorption on Si(111) surfaces. Only characteristic signatures of mono and dihydride phases are evidenced. At room temperature sticking of ${\mathrm{SiH}}_2$ or (${\mathrm{SiH}}_2$ ${)}_{\mathrm{n}}$ species for ${\mathrm{SiH}}_4$ and ${\mathrm{Si}}_2$ ${\mathrm{H}}_6$, respectively, are proposed and related to the back bonds of the dimer–adatom–stacking-fault model.