Structural and optical investigations of 1-, 2-, and 3-dimensional InAs quantum dot arrays

We have overgrown GaAs (0 0 1) substrates, patterned with dense square arrays of round-shaped nanometer-sized holes and trenches with stacked InAs quantum dots (QDs). Different periods of square hole arrays were overgrown at the same time and we observe a strong dependence of the evolving surface morphology on the period of the pre-pattern. QD pairs are observed only for large periods, whereas predominately single QDs form on patterns with smaller periods. We are able to assign the photoluminescence (PL) emission to specific QD layers and correlate the observed PL spectra of these QD arrays with the surface morphology. Furthermore, a comparison of the PL emission between conventionally grown and laterally ordered QDs reveals a comparable optical intensity of the ordered QDs.