Effect of rapid thermal annealing on electron emission and DX centers in strained InGaAs/GaAs single quantum well laser diodes

Thermal processing of strained In0.2Ga0.8 As/GaAs graded-index separate con finement heterostructure single quantum well laser diodes grown by molecula r beam epitaxy is investigated. It was found that rapid thermal annealing c an improve the 77K photoluminescence efficiency and electron emission from the active layer, due to the removal of nonradiative centers from the InGaA s/GaAs interface. Because of the interdiffusion of Al and Ga atoms, rapid t hermal annealing increases simultaneously the density of DX centers in the AlGaAs graded layer. The current stressing experiments of post-growth and a nnealed laser diodes are indicative of a corresponding increase in the conc entration of DX centers, suggesting that DX centers may be responsible for the degradation of laser diode performance. (C) 2000 Elsevier Science B.V. All rights reserved.