Fine structure in the bound exciton and multiple bound exciton luminescence from aluminium-doped silicon

A high-resolution investigation has been made of the luminescence associated with the decay of excitons bound to neutral Al acceptors in Si. The principal bound exciton line, associated with the transition A degrees X to A degrees , shows a thermalizing structure due to J-J coupling between the two holes and the electron at the acceptor site. The first satellite line on the low-energy side of the principal bound exciton line shows a doublet structure with a component separation and intensity ratio similar to two of the components of the principal line, identifying it with the transition A degrees XX to A degrees X. The second satellite line is a singlet. These observations support one of the recent models for multiple bound exciton transitions.