Ballistic transport at GHz frequencies in ungated HEMT structures

Sungmu Kang, Peter J. Burke, L. N. Pfeiffer, K. W. West

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


By measuring the ac impedance, we measure for the first time the crossover from diffusive (ωτ<1) to ballistic (ωτ>1) transport as a function of frequency (dc to 5 GHz) in a dc contacted 2d electron gas in the low electric field limit, where τ is the momentum scattering time. The geometry is an "ungated HEMT", meaning current flows through an ohmic contact into a 2d electron gas, laterally through the 2d electron gas, and out into a second ohmic contact; the 2d electron gas itself is not gated. At the measurement temperature (4.2 K), the low field mobility is 3.2×10 6 cm2/Vs. We also measure for the first time the frequency dependent contact impedance in this ballistic limit.

Original languageEnglish (US)
Pages (from-to)2013-2017
Number of pages5
JournalSolid-State Electronics
Issue number10-11 SPEC. ISS.
StatePublished - Oct 2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering


  • 2D electron gas
  • Ballistic transport


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