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

Author(s) Grillo, A.; Di Bartolomeo, A.; Urban, F.; Passacantando, M.; Caridad, J.M.; Sun, J.; Camilli, L.
Journal ACS Appl Mater Interfaces
Date Published 2020 Mar 09

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.

DOI 10.1021/acsami.0c00348
ISSN 1944-8252
Citation ACS Appl Mater Interfaces. 2020.

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