Imaging of Few-electron InAs Quantum Dots in InAs/InP Nanowires*

InAs quantum dots are promising contenders for nanoelectronics, spintronics and quantum information processing.~ Their large g-factor makes manipulation of electron spins easier at higher temperatures.~ InAs dots, as small as 10 nm long holding only a few electrons, can be formed by InP barriers in InAs/InP nanowire heterostructures grown using chemical beam epitaxy.~ Coulomb blockade transport measurements done using metal contacts and a back gate show excellent results [1].~ Using a liquid-He cooled scanning probe microscope, we imaged an InAs quantum dot that holds only one-electron, with the conducting tip as a movable gate [2].~ Simulations of electron wavefunctions in the dot show the effect of the back gate and the moveable tip. [1] M. Bj\"{o}rk\textit{ et al.}, Nano Letters\textbf{ 4}, 1621 (2004) [2] A. Bleszynski\textit{ et al.}, 28th Int. Conf. Physics of Semiconductors, 2006