Preparation of stair-step grooves by wet etching of AlAs/GaAs heterostructures and MOCVD growth of QWR

The possibility of preparing stair-step V- or U-grooves into a GaAs/AlAs heterostructure by isotropic and anisotropic wet chemical etching was studied. Several patterned structures with well-defined (100) planes of stairs were overgrown by MOCVD with the aim to realize quantum wires (QWRs) due to the selectivity of growth on these planes. This approach should allow for adjusting lateral and vertical dimensions independently as well as for a simple regulation of the density of QWRs. Samples were subsequently characterized by photoluminescence (PL), and it was supposed that the observed red shift could result from the presence of the QWRs.