Dresden 2003 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 49: Poster II
HL 49.37: Poster
Donnerstag, 27. März 2003, 16:30–19:00, HSZ/P2
Single electron tunneling in freely suspended phonon cavities — •Daniel Schröer1, Eva Höhberger1, Robert Blick1, Jörg Kotthaus1, and Werner Wegscheider2 — 1Center for NanoScience und Sektion Physik der Ludwigs-Maximilians-Universität München, 80539 München — 2Institut für Angewandte und Experimentelle Physik der Universität Regensburg, 93040 Regensburg
We integrate quantum dots in phonon cavities for studying single electron phonon interaction. This is achived by embedding two lateral tunnel coupled quantum dots in a freely suspended semiconductor nanostructure. The shape of the quantum dots is defined by electron beam lithography within the two dimensional electron gas of a GaAs/AlGaAs heterostructure. A sacrificial layer situated below allows for excavating the structure using a combined anisotropic and isotropic etch. Gate electrodes on the surface give control over the strength of tunnel barriers as well as the position of energy levels in the dots. The quantum dots are operated in the Coulomb blockade regime, allowing to observe single electron tunneling. Dimensional restrictions of the cavity cause a discretisation of phonon modes towards this direction and complete vanishing of the density of states for certain values of energy. Characteristic features of this discretisation should be recognisable in the quantum dot’s inelastic tunnel current, giving direct evidence of the reduced phonon spectrum as well as the controlled electron phonon interaction.