Auger effect in theMn2+luminescence ofCdF2:(Mn,Y) crystals

Abstract

The energy transfer between the ${\mathrm{Mn}}^{2+}$ ions and free electrons and electrons bound on shallow donors in ${\mathrm{CdF}}_2$:Mn,Y crystals has been examined. This so-called Auger effect on localized impurities turned out to be a very efficient quenching mechanism of the deep luminescent centers in semiconductors. Experimental evidence for such an effect is presented. It is proved that the dipole-dipole mechanism of the energy transfer is responsible for the luminescence quenching due to the free electrons unlike the quenching due to the weakly bound electrons where the exchange mechanism causes the decrease of the luminescence quantum efficiency. The theory presented here explains the experimental results very well. The Auger effect due to the free electrons is important at higher temperatures and was proved to be about 500 times more efficient than the Auger effect due to the shallow donors, which is important only at low temperatures. There are also arguments presented explaining problems with the designing of the dc-mode injection-type laser diodes based upon the intraimpurity emission.