Mixed dimensionality quantum heterostructures grown in axially modulated V grooves

We developed low-dimensional AlGaAs/GaAs heterostructures, which combine quantum well (QW), quantum wire (QWR), and quantum dot (QD) like structures along the bottom of a single V groove. By varying the groove geometry (through the use of electron-beam lithography), we could modify the morphology and control the size of each part of the grown structure on a submicron scale. We characterized the growth by cross-sectional atomic force microscopy and established the relation between substrate shape and growth front as function of grown thickness, as well as the formation of QWs and QWRs. In particular, we demonstrated the possibility to obtain a thicker, short QWR section in the center of a widening in a V-groove QWR. We confirmed the structural features, and specifically the lower band gap of the QD-like section, by low-temperature microphotoluminescence and cathodoluminescence spectroscopies.