Abstract
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 language | English |
---|---|
Journal | ACS Applied Materials and Interfaces |
Volume | 12 |
Issue number | 11 |
Pages (from-to) | 12998-13004 |
ISSN | 1944-8244 |
DOIs | |
Publication status | Published - 2020 |
Keywords
- Germanium arsenide
- 2D conduction
- Temperature-dependent conduction
- Field-effect transistors
- Carrier density
- Mobility
- Variable-range hopping