Published online by Cambridge University Press: 25 February 2011
Photoluminescence (PL) of Molecular Beam Epitaxy grown Er doped Ga 0.55Al0.45As has been studied under continuous and pulsed laser excitation . The observed PL lines are attributed to transitions from the first excited stated 4I13/2 to the ground state 4I15/2 . The life time of the 4I13/2 level is found to be 1 ms at 10K, which is comparable to the decay time observed in insulators.
Using two-beam experiments we show that there are losses (Auger effect) that occur during the PL excitation.We propose the following model for the Er PL excitation process: excitons bound to Er are created and decay non radiatively by energy transfer to the rare earth (which is the cause of the Er related PL) or to free carriers by Auger effect (which is the cause of the observed losses).