ERBIUM DOPING OF CRYSTALLINE AND AMORPHOUS-SILICON FOR OPTOELECTRONICAPPLICATIONS

In this work we demonstrate that efficient light emission at 1.54 mu m can be achieved when Er ions ape incorporated into crystalline Si or in heavily oxygen-doped amorphous and polycrystalline Si films (SIPOS) . We have found that temperature quenching of photo- and electrolumine scence, which is the major limitation towards the achievement of room temperature luminescence, can be strongly reduced by codoping these fi lms with oxygen. This impurity is already present in as-prepared SIPOS and it is introduced by ion-implantation in crystalline Si. Er lumine scence is obtained under both optical and electrical excitation and we demonstrate that excitation occurs through a carrier-mediated process . Electrical excitation is obtained by incorporating Er in properly de signed device structures. It is found that this excitation can occur b oth through the recombination of hole-electron pairs and through impac t excitation of the Er ions by hot electrons. These two mechanisms hav e different efficiencies and impact excitation is shown to prevail at room temperature. These data are presented and possible future develop ments are discussed.