Optical Properties of InAs Quantum Dot Array Ensembles with Predetermined Lateral Sizes from 20 to 40 nm

Cleaved edge overgrowth and selective area epitaxy were combined for the synthesis of InAs quantum dot (QD) arrays with lateral sizes from 20 to 40 nm. The optical properties were locally assessed by confocal photoluminescence spectroscopy experiments at liquid helium temperature. The emission lines redshift as the lateral size of the QDs is increased. In agreement with a narrow size distribution, significantly narrow emission lines are observed for measurements in QD ensembles. Excitation power dependent luminescence measurements were realized on QD ensembles. A shell filling behavior was observed. The same measurements realized on single QDs led to the observation of multiple excitonic effects. Polarization dependent luminescence measurements indicate the existence of in-plane optical anisotropy, which strictly follows in-plane morphological anisotropy of the QDs. These results are encouraging for the use of quantum dot arrays in quantum information science and technology, as well as for new device concepts. (C) 2010 The Japan Society of Applied Physics