3 μm photoluminescence from InGaAs quantum dots on GaAs

We use molecular beam epitaxy to grown coherently strained InGaAs islands on (100) GaAs substrates. The islands show room-temperature photoluminescence at 1.3 μm with a full width at half-maximum of only 28 meV. The integrated photoluminescence intensity is comparable to that of a quantum well. The islands are formed by depositing 22 monolayers of In0.3Ga0.7As with alternating beams of In, Ga, and As2. Atomic force microscopy measurements show that the islands are ellipsoidal sections with an average peak height of 24 nm. The intersection of the islands with the (100) plane is an ellipse whose major axis is along 011̄ and has a mean length of 54 nm, and whose minor axis is along 011 and has a mean length of 36 nm. The islands form a dense array with an areal coverage of about 40%.