Correlation of optical properties and interface morphology in type-II semiconductor heterostructures

Abstract

(Ga,In)As/GaAs/Ga(As,Sb) and (Ga,In)As/GaAs/Ga(N,As) type-II double quantum well heterostructures have been grown by metal-organic vapor phase epitaxy. A growth interruption procedure was used to intentionally modify the morphology of the internal interfaces. The heterostructures were investigated using continuous wave and time-resolved photoluminescence as well as optical pump–optical probe spectroscopy. We find a correlation between the interface morphology and optical and kinetic properties. A growth interruption of about 120 s yielded substantially smoother interfaces both on vertical as well as lateral length scales. On the other hand a considerably enhanced type-II recombination time as well as a longer electron tunneling time are observed. We attribute this to a reduced interface localization in case of smoother interfaces