Hydrogen passivation of aluminium atoms in crystalline silicon

Abstract

The total energy profile or surface for Al-H complexes in a large silicon cluster has been calculated using a self-consistent semi-empirical method. The diffusion path of hydrogen appears to be confined to a low-energy channel in the vicinity of the Si atom which is bonded directly to the Al atom at a substitutional site. The most stable configuration of this Al-H system results when the H atom is located at the bond-centred (BC) site. The system probably contains a Si-H-Al three-centre bond structure of bridging nature. This finding is compared with the Al-H pair assignment based on infrared experiments given by Stavola and co-workers which is based on the Al-H frequency calculated by DeLeo and Fowler.