Effect of growth interruption on Ga(N, As)/Ga(As, Sb)/Ga(N, As) type-II-"W" quantum well heterostructures

Ga(N,As)/Ga(As,Sb)/Ga(N,As) type-II-"W" quantum well heterostructures and Ga(As,Sb)/Ga(N,As) type-II double quantum well heterostructures have been grown by metal organic vapour phase epitaxy (MOVPE) on GaAs substrate. In particular the influence of growth interruptions on the interface morphology and the nitrogen incorporation efficiency have been studied. Ga(N,As)/Ga(As,Sb)/Ga(N,As) double quantum well structures have been characterized by high resolution x-ray diffraction, scanning transmission electron microscopy and photoluminescence spectroscopy. The internal interfaces were investigated with atomic force microscopy after application of a wet chemical etching technique that allows selective etching of all layers above. We observed a drastic effect of growth interruption duration on the nitrogen incorporation into Ga(N,As): Without growth interruption the nitrogen content was lowered strongly when grown on Ga(As,Sb) QWs. With increasing growth interruption an increase in nitrogen content is visible. The buried Ga(As,Sb) interface first showed a smoothing followed by a subsequent roughening due to the formation of holes of the Ga(As,Sb)-layer with longer growth interruption durations.