Project B1

Spin-dependent Spectroscopy of Electronic States in Individual and Coupled Quantum Dots

PIs: Prof. G. Abstreiter, Dr. A. Fontcuberta i Morral, Dr. D. Schuh, Prof. W. Wegscheider

The synthesis of single and coupled quantum dots for the electrical control of change and spin lifetimes of electrons and holes will be investigated. This project is concentrating on the complete control on the optical properties and therefore the geometry and arrangement of quantum dots and quantum dot molecules. Several fabrication techniques are being explored: a) Cleaved Edge Overgrowth b) self-assembly c) guided assembly on a cleaved facet and d) guided assembly along a GaAs nanowire.

References:

G. Schedelbeck, W. Wegscheider, M. Bichler, G.Abstreiter, Coupled Quantum Dots Fabricated by Cleaved Edge Overgrowth: From Artificial Atoms to Molecules, Science 278, 1792 (1997).

E. Uccelli, M. Bichler, S. Nuremberger, G. Abstreiter, A. Fontcuberta i Morral, Controlled synthesis of InAs wires, dot and twin dot array configurations by cleaved edge overgrowth, Nanotechnology 19, 045303 (2008).

A. Fontcuberta i Morral, C. Colombo, J. Arbiol, J.R. Morante, G. Abstreiter, Nucleation mechanism of gallium-assisted Molecular Beam Epitaxy growth of Gallium Arsenide nanowires, Appl. Phys. Lett. (2008).

B1-fig1

Atomic Force Microscopy of InAs quantum dot arrays obtained on the (110) cleaved facet of a AlAs/GaAs multilayer structure

B1-fig2

Transmission Electron Micrograph of a GaAs nanowire bundle, obtained in our MBE