Free GaAs surfaces studied using a back-gated undoped GaAs/AlxGa1-xAs heterostructure

A. Kawaharazuka, T. Saku, C. A. Kikuchi, Y. Horikoshi, Y. Hirayama

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We study the free GaAs surface by using a back-gated undoped GaAs/AlxGa1-xAs heterostructure. This structure is suitable in investigating the free GaAs surface since a two-dimensional electron gas is induced by the back-gate bias in the undoped heterostructure. We compare the channel depth dependence of the transport characteristics with two different models of the free GaAs. The "midgap pinning model" assumes a constant surface Fermi level and an alternative approach called the "frozen surface model" assumes a constant surface charge density. The experimental results indicate that the frozen surface model appropriately describes free GaAs surfaces at low temperatures although the midgap pinning model is widely accepted. This is because charges cannot be transferred to the free GaAs surface at low temperatures.

Original languageEnglish
Article number245309
Pages (from-to)2453091-2453098
Number of pages8
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number24
Publication statusPublished - 2001 Aug 15
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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