Midinfrared photoluminescence of InAsSb quantum dots grown by liquid phase epitaxy

Photoluminescence in the 2–5 μm spectral region is reported from InAs1−xSbx quantum dots grown from the liquid phase at 580 °C on an InAs (100) substrate. Atomic force microscopy shows that coalesced quantum dots and then isolated quantum dots are formed with increasing Sb composition (x=0.2–0.3) and strain. The 4 K photoluminescence of the isolated and coalesced quantum dots was observed to peak in the midinfrared at 289 and 316 meV, (4.29 and 3.92 μm), respectively. These peaks are due to type II transitions and begin to quench at temperatures above 100 K as holes become thermally activated out of the quantum dot confinement potential.