Stark Shifts and Excitonic Effects in Semiconductor Quantum Wells and Superlattices

Abstract

In this set of lectures I shall give a brief theoretical description of Stark shifts and excitonic effects in semiconductor quantum wells and superlattices. These two topics have stimulated a significant amount of academic research. They are also at the heart of novel opto-electronic devices [1,2] (e.g. fast electro-optical modulators). For the first time the room temperature operation of some semiconductor devices is possible only due to the existence of bound electron-hole pairs: the excitons. The excitons are more stable in quantum wells than in bulk materials, due to their confinement in a narrow slab by large potential barriers. They can also be shifted in energy by an external electric field without being bleached. These two factors explain their technological relevance.