Observation of 2D Conduction in Ultrathin Germanium Arsenide Field-Effect Transistors

Alessandro Grillo, Antonio Di Bartolomeo, Francesca Urban, Maurizio Passacantando, Jose M. Caridad, Jianbo Sun, Luca Camilli

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We report the fabrication and electrical characterization of germanium arsenide (GeAs) field-effect transistors with ultrathin channels. The electrical transport is investigated in the 20-280 K temperature range, revealing that the p-type electrical conductivity and the field-effect mobility are growing functions of temperature. An unexpected peak is observed in the temperature dependence of the carrier density per area at ∼75 K. Such a feature is explained considering that the increased carrier concentration at higher temperatures and the vertical band bending combined with the gate field lead to the formation of a two-dimensional (2D) conducting channel, limited to few interfacial GeAs layers, which dominates the channel conductance. The conductivity follows the variable-range hopping model at low temperatures and becomes the band-type at higher temperatures when the 2D channel is formed. The formation of the 2D channel is validated through a numerical simulation that shows excellent agreement with the experimental data.
Original languageEnglish
JournalACS Applied Materials and Interfaces
Issue number11
Pages (from-to)12998-13004
Publication statusPublished - 2020


  • Germanium arsenide
  • 2D conduction
  • Temperature-dependent conduction
  • Field-effect transistors
  • Carrier density
  • Mobility
  • Variable-range hopping

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