Towards a germanium and silicon laser: The history and the present

Abstract

Various theoretical as well as empirical considerations about how to achieve lasing between the conduction and valence bands in indirect band gap semiconductors (germanium and silicon) are reviewed, starting from the dawn of the laser epoch in the beginning of the sixties. While in Ge the room-temperature lasing under electrical pumping has recently been achieved, in Si this objective remains still illusory. The necessity of applying a slightly different approach in Si as opposed to Ge is stressed. Recent advances in the field are discussed, based in particular on light-emitting Si quantum dots.