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Quantized Conduction and High Mobility in Selectively Grown InGa As Nanowires x
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Cezar B. Zota, David Lindgren, Lars-Erik Wernersson, and Erik Lind ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.5b03318 • Publication Date (Web): 20 Sep 2015 Downloaded from http://pubs.acs.org on September 23, 2015
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ACS Nano
Quantized Conduction and High Mobility in Selectively Grown InxGa1-xAs Nanowires Cezar B. Zota,*,† David Lindgren,§ Lars-Erik Wernersson† and Erik Lind† †
Department of Electrical and Information Technology, Lund University, Box 118, 22100 Lund,
Sweden. §
Division of Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden
KEYWORDS Field effect transistors, nanowire, electric transport, mobility, InGaAs, ballistic transport, selective regrowth, photoluminescence, Raman
ABSTRACT
We report on measured quantized conductance and quasi-ballistic transport in selectively regrown In0.85Ga0.15As nanowires. Very low parasitic resistances obtained by regrowth techniques allow us to probe the near-intrinsic electrical properties, and we observe several quantized conductance steps at 10 K. We extract a mean free path of 180 ± 40 nm and an
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effective electron mobility of 3300 ± 300 cm2/V⋅s, both at room-temperature, which are among the largest reported values for nanowires of similar dimensions. In addition, optical characterization of the nanowires by photoluminescence and Raman measurement is performed. We find an unintentional increase of Indium in the InxGa1-xAs composition relative the regrown film layer, as well as partial strain relaxation.
Indium-rich InxGa1-xAs nanowires have gathered much recent research attention due to their excellent electron transport properties.1 In particular, InAs nanowires have been shown to have least an order of magnitude higher mobility than Silicon nanowires.2,3 Moreover, the ease by which ohmic contacts are formed to InxGa1-xAs, and the possibility of low-defect high-k oxides interfaces, has made InxGa1-xAs one of the primary considerations as the replacement for Silicon channels in n-type metal-oxide-semiconductor field effect transistors (MOSFETs).4–7 The implementation of III-V MOSFETs such as InxGa1-xAs will likely be in the form of 1D nanowires with diameters below 30 nm.8 The use of nanowires as the channel in MOSFETs offers enhanced performance compared to traditional planar channels, through improved electrostatic control. The combination of high-mobility materials and the short gate-lengths (~30 nm) of state-of-the-art MOSFETs indicate operation in the ballistic or quasi-ballistic regime. Together with 1D channels, such devices display unique characteristics, notably quantized conduction, step-like features in the conductance at low temperatures. Several methods of fabricating InxGa1-xAs nanowires have been reported. In particular, nanowires grown by the vapor-liquid-solid (VLS) technique, employing a metal particle catalyst, have been widely studied.9 VLS-grown InAs nanowires, for instance, exhibit mobility ranging
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from 2000 to 5000 cm2/Vs at nanowire diameters of
