Fig 1: interdigital transducer to launch surface acoustic waves This piezoelectric field and the mechanical lattice distortion is used to alter the properties of the nanostructures. There we take particular emphasis on quantised energy levels and the quantized nature of electrons and photons. One main application is the single electron maniplation by the piezoelectric SAW field. Like a turnstile device the SAW pumps electrons through the quantised energy levels of one- and zerodimensional systems. This results in a quantised charge transport I = ef (see Fig. 2).
Fig. 2: quantised current transport by the SAW Besides semiconductor quantum dots one of our main interests are carbon nanotubes CNT (see Fig. 3)
Fig. 3: contacted single-walled carbon nanotubes These ideal one-dimensinal systems can be prepared to be quantum dots by contacting them with nanostrucured metal fingers. One main focus is to investigate the influence of SAW on the CNT properties. Also with this system we have already realised a quantised charge transport by taking advantage of the piezoelectric SAW potential. Another onedimensional semiconductor system that we work on are galliumnitride whiskers (see Fig. 4). By using ebeam lithography we are processing very small contacts to the nanowires in order to alter the energy spectrum by the SAW.
Fig. 4: a contacted GaN-nanowhisker" There are also efforts to create a deterministic single photon source by the use of a SAW -> more informations are coming soon...