Quantum wires and self-assembled quantum dots
A main effort in our group is the fabrication and characterisation of semiconductor quantum wires and quantum dots which are the basis for novel quantum devices. These quantum structures are directly synthesized by molecular beam epitaxy (MBE) or are fabricated by various lithographical techniques, especially e-beam lithography. Quantum wires which are of interest due to their special electronic transport properties are realised by cleaved edge overgrowth in GaAs based systems. Self assembled quantum dots are fabricated by Stranski-Krastanov growth mode of lattice mismatched systems such as Si/Ge and InAs/GaAs. Selforganisation of quantum dots is achieved by using for example step ordering on vicinal surfaces as templates. Combination of cleaved edge overgrowth with self assembly is a new method of atomically precise ordering. Examples of chains of InAs dots on AlAs stripes are shown in the figure. This work is supported financially by DFG via SFB631.
