Terahertz optical-Hall effect characterization of two-dimensional electron gas properties in AlGaN/GaN high electron mobility transistor structures
Abstract
The free-charge carrier mobility, sheet density, and effective mass of a two-dimensional electron gas are exemplarily determined in the spectral range from 640 GHz to 1 THz in a AlGaN/GaN heterostructure using the optical-Hall effect at room temperature. Complementary midinfrared spectroscopic ellipsometry measurements are performed for analysis of heterostructure constituents layer thickness, phonon mode, and free-charge carrier parameters. The electron effective mass is determined to be (0.22±0.04)m0. The high-frequency sheet density and carrier mobility parameters are in good agreement with results from dc electrical Hall effect measurements, indicative for frequency-independent carrier scattering mechanisms of the two-dimensional carrier distribution.
- Publication:
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Applied Physics Letters
- Pub Date:
- February 2011
- DOI:
- Bibcode:
- 2011ApPhL..98i2103S
- Keywords:
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- aluminium compounds;
- carrier mobility;
- effective mass;
- gallium compounds;
- Hall effect;
- high electron mobility transistors;
- III-V semiconductors;
- phonons;
- two-dimensional electron gas;
- 85.30.Tv;
- 72.20.Fr;
- 72.20.My;
- 71.18.+y;
- Field effect devices;
- Low-field transport and mobility;
- piezoresistance;
- Galvanomagnetic and other magnetotransport effects;
- Fermi surface: calculations and measurements;
- effective mass g factor