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Quantum dots formed in InAs/InP heterostructure nanowires are attractive candidates for nanoelectronics, spintronics, and quantum information processing. Confinement of electrons within nanowires allows charge to be manipulated at relatively high temperatures, whilst the large g-factor of InAs eases the task of manipulating electron spins. InAs nanowires are grown by chemical beam epitaxy. InP tunnel barriers are incorporated into the wire during the growth process, forming single, or multiple tunnel-coupled quantum dots [1]. A liquid-Helium cooled scanning probe microscope is used to measure the conductance through a nanowire quantum-dot system as a function of tip position. We have demonstrated the to use of Coulomb blockade resonances to image a one-electron single quantum dot defined in these systems [2]. We propose that by varying tip position, tip voltage and backgate voltage, it is possible to arbitrarily tune the charge and polarization state of a double-dot with a scanning probe microscope.
[1] M. Björk et al., Nano Letters 4, 1621 (2004).
[2] A. Bleszynski et al., 28th Int. Conf. Physics of Semiconductors, 2006.
This work was supported at Harvard University by the NSEC, NSF PHY-06-46094
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