Temperature dependent effective mass in AlGaN/GaN high electron mobility transistor structures
Abstract
The temperature-dependence of free-charge carrier mobility, sheet density, and effective mass of a two-dimensional electron gas in a AlGaN/GaN heterostructure deposited on SiC substrate is determined using the THz optical Hall effect in the spectral range from 0.22 to 0.32 THz for temperatures from 1.5 to 300 K. The THz optical Hall-effect measurements are combined with room temperature mid-infrared spectroscopic ellipsometry measurements to determine the layer thickness, phonon mode, and free-charge carrier parameters of the heterostructure constituents. An increase of the electron effective mass from (0.22±0.01)m0 at 1.5 K to (0.36±0.03)m0 at 300 K is observed, which is indicative for a reduction in spatial confinement of the two-dimensional electron gas at room temperature. The temperature-dependence of the mobility and the sheet density is in good agreement with electrical measurements reported in the literature.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 05, 2012
- Source ID
- 10.1063/1.4765351
Entities
People
- C. M. Herzinger
- E. Janzén
- J. A. Woollam
- Jr-tai Chen
- Mathias Schubert
- N. Ben Sedrine
- P. Kühne
- S. Schöche
- T. Hofmann
- U. Forsberg
- V. Darakchieva
Organizations
- Army Research Office
- Linköping University
- National Institute of Standards and Technology
- Technical University of Lisbon
- University of Nebraska–Lincoln