FORMATION AND CHARACTERIZATION OF COUPLED QUANTUM DOTS (CQDS) BY SELECTIVE-AREA METALORGANIC VAPOR-PHASE EPITAXY

We have demonstrated novel GaAs quantum dot arrays coupled to quantum wire networks, that is, coupled quantum dots (CQDs) formed by selectiv e area metalorganic vapor phase epitaxy (SA-MOVPE). First, GaAs buffer layers are grown on GaAs(001) substrates with SiNx square masks in 40 0 nm periodicity to [100] and [010] directions. GaAs cross-wire struct ures with pyramids at the corners are obtained. Next, GaAs/AlGaAs quan tum wells are overgrown on top of these structures. Quantum dots (QDs) and quantum wires (QWRs) are formed at the top portions of the pyrami ds and at the ridges of wires, respectively. The cathodoluminescence ( CL) image shows strong emission from the top portions of the pyramids, which suggests that high-quality CQD structures are formed by SA-MOVP E.