Non-equilibrium Green's function calculation for GaN-based terahertz-quantum cascade laser structures

H. Yasuda, National Institution of Information & Communication Technology (NICT)
T. Kubis, Birck Nanotechnology Center, Purdue University
I. Hosako, National Institution of Information & Communication Technology (NICT)
K. Hirakawa, Tokyo University

Date of this Version



J. Appl. Phys. 111, 083105 (2012)


Copyright (2012) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 111, 083105 (2012) and may be found at The following article has been submitted to/accepted by Journal of Applied Physics. Copyright (2012) H. Yasuda, T. Kubis, I. Hosako and K. Hirakawa. This article is distributed under a Creative Commons Attribution 3.0 Unported License.


We theoretically investigated GaN-based resonant phonon terahertz-quantum cascade laser (QCL) structures for possible high-temperature operation by using the non-equilibrium Green's function method. It was found that the GaN-based THz-QCL structures do not necessarily have a gain sufficient for lasing, even though the thermal backfilling and the thermally activated phonon scattering are effectively suppressed. The main reason for this is the broadening of the subband levels caused by a very strong interaction between electrons and longitudinal optical (LO) phonons in GaN. (C) 2012 American Institute of Physics. []


Nanoscience and Nanotechnology