Formation characteristics of shape-engineered InAs/InAlGaAs quantum dots grown on InP substrates

This article reports the structural and optical properties of shape-engineered InAs/InAlGaAs quantum dots (QDs) on InP substrates formed using an alternate growth method (AGQDs), where a thin InAs layer (0.8 or 1 monolayer) and a thin InAlGaAs layer (1 monolayer) were deposited alternately. For five-stacked AGQD layers, a double-peak feature was observed in the photoluminescence (PL) spectra. The two peaks were related to two different QD branches as confirmed by excitation-power-dependent PL. Observation of a double-peak feature in the PL spectra indicated that the growth conditions for the AGQD layers were not optimized. A slight increase in growth temperature resulted in the merging of the double-peak feature to a single peak with a relatively narrow PL linewidth.