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Journal of Nanomaterials
Volume 2014, Article ID 850915, 5 pages
http://dx.doi.org/10.1155/2014/850915
Research Article

Terahertz Performance of a GaN-Based Planar Nanochannel Device

1Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
2State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China

Received 13 January 2014; Revised 16 March 2014; Accepted 25 March 2014; Published 10 April 2014

Academic Editor: Sheng-Po Chang

Copyright © 2014 K. Y. Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Using a combined two-dimensional-three-dimensional (2D-3D) ensemble Monte Carlo (EMC) model, the performance of a planar nanochannel device is studied at the terahertz (THz) region. The device is based on a GaN/AlGaN heterostructure in which a two-dimensional electron gas (2DEG) forms at the interface. Simulation results reveal that, at low working frequencies, the performance of the device is almost frequency independent. However, when the working frequency is higher than 0.5 THz, obvious enhancements in the device performance have been observed. The enhancements are characterized by two resonant peaks at frequencies of about 4 THz and 8 THz. Also, the frequency-dependent performance exhibits nonmonotonicity. Further studies show that the performance enhancements can be attributed to the excitations of 2D plasma waves in the device, with the emergence of the above resonant peaks corresponding to the formation of standing plasma waves. Moreover, simulation results show that the device performance increases monotonically with signal amplitude, when the device is unbiased. However, when a DC bias is applied, the performance remains almost unchanged for large signals but is significantly enhanced for small signals. Therefore, the device performance shows a strong nonmonotonic dependence on signal amplitude, and its minimal value occurs when the signal amplitude is only about times the DC bias.