Effects of the impurity-impurity and impurity-host interactions on the charge density and the related processes

摘要

Transitions via impurities, in addition to transitions from the valence band to the conduction band insemiconductors increase the generation of electron-hole pairs. These transitions lead to alterations inthe electronic density around the impurities, and as a consequence, to modifications in the forces on theimpurities. In many cases it leads to an increase in the non-radiative recombination. The understandingof these processes at an atomic scale is very important for the physics of doped semiconductors, andtechnologically, for optoelectronic and spintronic devices. Using simple approximate models based onfirst-principles, the charge density and the related processes are analyzed. The results show that anincrease in the impurity-host interaction or an increase in the concentration of the impurity leads tosmall variations in the density around the impurities for different charge states and a decrease in theeffective Coulomb repulsion. These facts reduce the mechanism of non-radiative recombination viamulti-phonon emission.