Terahertz optical-Hall effect characterization of two-dimensional electron gas properties in AlGaN/GaN high electron mobility transistor structures

Authors

S. Schöche, University of Nebraska–LincolnFollow
Junxia Shi, Cornell University
A. Boosalis, University of Nebraska–Lincoln
P. Kühne, University of Nebraska–Lincoln
C. M. Herzinger, J.A. Woollam Co. Inc.
John A. Woollam, J.A. Woollam Co. Inc.Follow
W. J. Schaff, Cornell University
L. F. Eastman, Cornell University
M. Schubert, University of Nebraska–LincolnFollow
Tino Hofmann, University of Nebraska–LincolnFollow

Date of this Version

2011

Citation

APPLIED PHYSICS LETTERS 98, 092103 (2011); doi:10.1063/1.3556617

Comments

Copyright 2011 American Institute of Physics

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.