Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 58: Poster Session Transport & Matter at Low Temperature
TT 58.11: Poster
Thursday, March 14, 2013, 15:00–19:00, Poster D
Quantum-point contact based charge read-out for the InAs nanowire tip of a scanning tunneling microscope — •Sebastian Wüsten1, Kilian Flöhr1, Eugen Kaganovitch1, Nils Freitag1, Kamil Sladek2, Mihail Lepsa2, Hilde Hardtdegen2, Marcus Liebmann1, Thomas Schäpers2, and Markus Morgenstern1 — 1II. Physikalisches Institut, RWTH Aachen and JARA-FIT, 52074 Aachen, Germany — 2Peter Grünberg Institut, Forschungszentrum Jülich and JARA-FIT, 52425 Jülich, Germany
Proximal on-chip read-out of the current of a scanning tunneling microscope (STM) could improve low-current operation of the STM dramatically down to the detection of single tunneling electrons. Recently, we have demonstrated that InAs nanowires work as semiconducting tips for STM providing atomic resolution [1]. The wires grown by metal-organic vapor phase epitaxy (MOVPE) without catalysts are picked up individually with a sharp indium tip exploiting adhesion forces and subsequently, placed on the edge of a GaAs wafer [2]. Further on, this process creates the possibility of circuitry on the wafer, i.e. within 1 µm from the tip apex. As a first step in that direction, we used a quantum point contact (QPC) processed into an AlGaAs/GaAs heterostructure [3]. Different QPC shapes are characterized by low-temperature (>0.3 K) transport measurements with respect to the nanowire read-out.
[1] K. Flöhr, K. Sladek, H. Y. Günel, M. I. Lepsa, H. Hardtdegen, M. Liebmann, Th. Schäpers, M. Morgenstern, Apl. Phys. Lett., accepted (2012)
K. Flöhr et al., Rev. Sci. Instrum. 82, 113705 (2011)
I. Shorubalko et al., Nano Lett. 8, 382 - 385 (2008)