ABSTRACT
Carrier localisation and transport were studied in GaAs/AlGaAs heterostructures grown by metal organic chemical vapour deposition on patterned substrates using cathodoluminescence (CL). In inverted-pyramid quantum dot structures carrier recombination in the quantum dot, quantum wires and quantum wells is observed. Using CL wavelength dispersive images, bandstructure variations in these structures can be observed. We find indications for efficient carrier coupling from a Ga rich vertical quantum wire to the quantum dot. We show that tapered quantum wires form at the intersection of the pyramid sidewalls and discuss their possible use as exciton accelerators. Tapered quantum wires can also be generated by growth on V-grooves with lateral variation of the groove width. When the transition zone between different groove segments is abrupt, carriers are localised in QWR segments. On the other hand, variable width V-groove systems with long transition zones are candidates for efficient carrier coupling between different QWR zones.
