Towards defect-free 1-D GaAs/AlGaAs heterostructures based on GaAs nanomembranes.

Optimization of AlAs/AlGaAs quantum well heterostructures on on-axis and misoriented GaAs (111)B

We report systematic growth optimization of high Al-content AlGaAs, AlAs, and associated modulation-doped quantum well (QW) heterostructures on on-axis and misoriented GaAs (111)B by molecular beam epitaxy. Growth temperatures TG> 690 C and low As4 fluxes close to group III-rich growth significantly suppress twin defects in high-Al content AlGaAs on on-axis GaAs (111)B, as quantified by atomic ...

Electron mobilities approaching bulk limits in "surface-free" GaAs nanowires.

Achieving bulk-like charge carrier mobilities in semiconductor nanowires is a major challenge facing the development of nanowire-based electronic devices. Here we demonstrate that engineering the GaAs nanowire surface by overcoating with optimized AlGaAs shells is an effective means of obtaining exceptionally high carrier mobilities and lifetimes. We performed measurements of GaAs/AlGaAs core-s...

Laterally defined freely suspended quantum dots in GaAs/AlGaAs heterostructures.

Free-standing beams containing a two-dimensional electron system are shaped from a GaAs/AlGaAs heterostructure. Quantum point contacts and (double) quantum dots are laterally defined using metal top gates. We investigate the electronic properties of these nanostructures by transport spectroscopy. Tunable localized electron states in freely suspended nanostructures are a promising tool to invest...

New approach to local anodic oxidation of semiconductor heterostructures.

We have experimentally explored a new approach to local anodic oxidation (LAO) of a semiconductor heterostructures by means of atomic force microscopy (AFM). We have applied LAO to an InGaP/AlGaAs/GaAs heterostructure. Although LAO is usually applied to oxidize GaAs/AlGaAs/GaAs-based heterostructures, the use of the InGaP/AlGaAs/GaAs system is more advantageous. The difference lies in the use o...

ON THE MOBILITY OF GaAs-AlGaAs HETEROSTRUCTURES WITH AN IMPURITY LAYER IN THE GaAs