Quantitative compositional profiles of enhanced intermixing in GaAs/AlGaAs quantum well heterostructures annealed with and without a SiO2 cap layer

Cross-sectional scanning transmission electron microscopy together with energy-dispersive x-ray spectroscopy (EDX) was used to quantitatively analyze quantum well intermixing (QWI) of a GaAs quantum well (QW) structure with AlGaAs barriers for samples capped with SiO2 or uncapped. Energy-dispersive x-ray analysis shows inter-diffusion of Ga and As into the SiO2 layer and Si into top GaAs layer. The enhanced QWI due to rapid thermal annealing …