Demonstration of Confined Electron Gas and Steep-Slope Behavior in Delta-Doped GaAs-AlGaAs Core-Shell Nanowire Transistors.
Strong surface and impurity scattering in III-V semiconductor-based nanowires (NW) degrade the performance of electronic devices, requiring refined concepts for controlling charge carrier conductivity. Here, we demonstrate remote Si delta (δ)-doping of radial GaAs-AlGaAs core-shell NWs that unambiguously exhibit a strongly confined electron gas with enhanced low-temperature field-effect mobilities up to 5 × 10(3) cm(2) V(-1) s(-1). The spatial separation between the high-mobility free electron gas at the NW core-shell interface and the Si dopants in the shell is directly verified by atom probe tomographic (APT) analysis, band-profile calculations, and transport characterization in advanced field-effect transistor (FET) geometries, demonstrating powerful control over the free electron gas density and conductivity. Multigated NW-FETs allow us to spatially resolve channel width- and crystal phase-dependent variations in electron gas density and mobility along single NW-FETs. Notably, dc output and transfer characteristics of these n-type depletion mode NW-FETs reveal excellent drain current saturation and record low subthreshold slopes of 70 mV/dec at on/off ratios >10(4)-10(5) at room temperature.
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Morkötter
‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States.
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Jeon
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Rudolph
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Loitsch
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Spirkoska
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.|∥Institute for Advanced Study, Technische Universität München, Garching 85748, Germany.
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Hoffmann
§Department of Chemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany.
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Döblinger
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Matich
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Finley
‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States.
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Lauhon
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.|∥Institute for Advanced Study, Technische Universität München, Garching 85748, Germany.
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Abstreiter
†Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching 85748, Germany.
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Koblmüller
D000535:Aluminum / Q000737:chemistry*; D001152:Arsenicals / Q000737:chemistry*; D004583:Electrons; D005708:Gallium / Q000737:chemistry*; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry*; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry
D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium; D000535:Aluminum; D012825:Silicon
Delta-doped GaAs-AlGaAs core−shell nanowires; atom probe tomography; field effect transistors; transport; two-dimensional electron gas formation