DFT study of the dissociative adsorption of H2S molecule on the Si(111)-7×7 surface

Abstract

Abstract Density functional theory calculation has been used to investigate the dissociative adsorption of hydrogen sulfide molecules on the Si(1 1 1)-7 × 7 surface. The reaction pathways for four hydrogen sulfide molecules dissociation over the adatom and rest atom sites are explored theoretically. The calculated results demonstrate that the initial dissociation of the first H 2 S molecule on both different sites to form the adsorbed SH species is no energy barrier. The elevated temperature can result in further S H bond dissociation, which is started by an SH insertion, and then followed by an H-transfer process. Subsequently, the second H 2 S attacks the adatom site (Si a ), H atoms from the S H of the second H 2 S and surface Si a H are extracted to release the gas phase H 2 , and then the SH species from the second H 2 S occupies on the Si a site. Furthermore, the SH species inserts into Si Si backbond of the adatom, followed by an H-transfer process. In the same way, the SH species from the third and the fourth H 2 S molecule are also inserted into remnant Si Si backbonds of the adatom followed by an H-transfer process up to the formation of Si 4+ state.