Improvement in size distributionbasic solid state physics and optical properties of InAs/GaAs QDs by post growth thermal treatment

摘要

We investigated the effect of rapid thermal annealing fromto'050-''r oh stacked InAs/GaAs quantum dots (QDs)covered with GaAs"and Inol9Ga081As layers. Large blue-shiftj^oSltionsiear1y 380 meV (1187 ntn to 870 nrn)in iiGaAs capped samples together withimpnwement the,Photoltniiinescence integrated intensity ofMore than five times, The strong narrowing of the photolumi-nes in both GaAs (as narrow as 8 meV) andlnQaAs capped samples show an improvement of the size distribution of the Qns. In addition, a significant reduction ofthe energy spacing (AE2_1) between ground state and first ex-cited state emissions were found in both GaAs and InGaAscapped quantum dots' due to interface inter-diffusion inducedby thermal treatment. The excited state filling experiments forInGaAs capped sample annealed at 950 °C exhibits quantumwell like behavior where as, the GaAs capped sample shows ashoulder in high energy side might be due to first excitedstate of QDs.