PHOTOLUMINESCENCE INVESTIGATION OF THE CARRIER CONFINING PROPERTIES OF MULTIQUANTUM BARRIERS

A comparative luminescence study of two Ga-0.52 In0.48P-(Al0.5Ga0.5)(0 .52)In0.48P single-quantum-well (SQW) samples with bulk and multiquant um barrier (MQB) barriers is presented, When excess carriers are only created in the quantum wells (QW's) of the samples by resonant excitat ion using a dye laser, the luminescence efficiency of both samples as a function of temperature is found to be essentially identical, We fin d, therefore, no evidence for any enhancement in the confining potenti al of the MQB sample over the bulk barrier sample, From Arrhenius plot s of the intregrated luminescence intensity, it is found that carrier loss from the QW is dominated by a nonradiative loss mechanism with an activation energy considerably smaller than that expected from direct thermal loss of electrons and holes into the barriers. We suggest tha t the improved device characteristics reported for lasers containing M QB's is due to effects other than the quantum interference of electron s.