Direct epitaxial growth of (AlGa)As/GaAs quantum wires by orientation-dependent metalorganic vapour phase epitaxy

Abstract

The direct growth of (AlGa)As/GaAs quantum wire structures using metalorganic vapour phase epitaxy (MOVPE) is investigated. The present concept takes advantage of the different growth rates of GaAs and (AlGa)As on (100) and {111} planes to transfer a trapezoidal GaAs starting structure with dimensions in the μm-range into a quantum wire structure in the nm-range. For stripe dimensions below 500 nm significant changes in growth behaviour (enhanced growth rates and for special cases also the formation of other crystallographic facets) are observed by using scanning electron microscopy (SEM) studies. Based on these findings (AlGa)As/GaAs quantum wire structures are realized with lateral structure sizes of 30 nm as proved by SEM. The luminescence properties of these structures, which are determined by standard and polarization-dependent photoluminescence excitation spectroscopy, are presented and discussed in comparison to the properties of quantum well structures.