AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Tuesday Sessions
       Session NS+EM-TuM

Paper NS+EM-TuM3
Few Electron SiGe Quantum Dots

Tuesday, November 1, 2005, 9:00 am, Room 210

Session: Nanoscale Electronic Devices & Detection
Presenter: L.J. Klein, University of Wisconsin
Authors: L.J. Klein, University of Wisconsin
S. Goswami, University of Wisconsin
K.A. Slinker, University of Wisconsin
S.N. Coppersmith, University of Wisconsin
D. Savage, University of Wisconsin
M.G. Lagally, University of Wisconsin
M.A. Eriksson, University of Wisconsin
Correspondent: Click to Email
Spins in silicon quantum dots are promising qubits for quantum information processing. Here we present an approach to combine trenchline and metal gates to fabricate quantum dots in modulation doped Si/SiGe heterostructures. Electron-beam lithography and reactive ion etching are used to define single and tunnel coupled double dots. Both Schottky and in-plane two-dimensional electron gas gates are used. Transport measurements at 0.2 K for the single and tunnel coupled double dots show Coulomb blockade with single electron charging. For the double quantum dots a transition from a single to split peaks are observed as voltages applied to the gates became more negative. A transition is observed from a large single dot to two tunnel coupled quantum dot with a well defined tunnel coupling between pairs of quantum dots. The tunnel coupling between the dots is determined by the width of the channel between the dots. To achieve a higher control of the tunnel coupling between the dots we integrate metal gates on the top of the channel in addition to side gates. The fabricated quantum structures are stable over long periods of time with minimal charge noise fluctuations. We also discuss progress towards the achievement of few electron dots using both etched and Schottky gates for electrostatic confinement.