Behaviour of silicon surfaces during some gaps chemisorption. II. Chemisorption on intrinsic-type surfaces

A previous article [1] described the experimental plant destined to the stu dy of chemisorption on semiconductive surfaces of the extrinsic type, as we ll ws the operating procedure for the evidentiation of the electronic trans fer (e.t.) direction at the solid-gas interface. The study regarding the ch emisorption of the same gases on pure silicon surfaces (intrinsic semicondu ctor when the number of negative charge hearers is equal to the positive ch arge bearers) has evidentiated situations where the surface has either a "p " or "n" type behaviour, or behave simultaneously as a "p" and "n" type sur face, or differ from both "p" and "n" type ones. Starting from these experi mental remarks, semiempirical quanto-chemical calculations were initiated, based on the MNDO (Modified Neglect of Differential Overlap) method worked out by Dewar [2], in order to establish the interface electronic mechanisms during chemisorption.