The band alignment of InAs quantum dots (QDs) embedded in GaAsSb barriers with various Sb compositions is investigated by photoluminescence (PL) measurements. InAs/GaAsSb samples with 13 and 15 Sb compositions show distinct differences in emission spectra as the PL excitation power increases. Whilst no discernible shift is seen for the 13 sample, a blue-shift of PL spectra following a 1/3 exponent of the excitation power is observed for the 15 sample suggesting a transition from a type I to type II band alignment. Time-resolved PL data show a significant increase in carrier lifetime as the Sb composition increases between 13 and 15 implying that the transformation from a type I to type II band alignment occurs between 13 and 15 Sb compositions. These results taken together lead to the conclusion that a zero valence band offset (VBO) can be achieved for the InAs/GaAsSb system in the vicinity of 14 Sb composition.
ASJC Scopus subject areas
- Physics and Astronomy(all)