Demonstration of confined electron gas and steep-slope behavior in delta-doped GaAs-AlGaAs core-shell nanowire transistors

S. Morkötter*, N. Jeon, D. Rudolph, B. Loitsch, D. Spirkoska, E. Hoffmann, M. Döblinger, S. Matich, J. J. Finley, L. J. Lauhon, G. Abstreiter, G. Koblmüller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

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 × 103 cm2 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 >104-105 at room temperature.

Original languageEnglish (US)
Pages (from-to)3295-3302
Number of pages8
JournalNano letters
Volume15
Issue number5
DOIs
StatePublished - May 13 2015

Keywords

  • Delta-doped GaAs-AlGaAs core-shell nanowires
  • atom probe tomography
  • field effect transistors
  • transport
  • two-dimensional electron gas formation

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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