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Proceedings Paper

Non equilibrium electrons in THz quantum cascade lasers
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Paper Abstract

We compare the electrical power dependence of the lattice temperature and the electronic temperature of THz quantum cascade lasers (QCLs) operating in the range 2.5- 3.8 THz and based on a resonant-phonon and bound-to-continnum quantum design. This analysis is performed by means of microprobe band-to-band photoluminescence experiments carried out on operating THz QCLs both below and above the lasing threshold. Thermalized non-equilibrium hot-electron distributions are found in both classes of QCLs. While in the case of bound-to-continuum devices a unique value of the electronic temperature is found in the active region minibands, in the case of resonant-phonon devices we found that the upper radiative state, in the lasing range, heats up to ~ 200 K, more than 100 K with respect to the ground state levels. From the measured thermal resistance and the power dependence of the ground state electronic temperature we obtain in the case of resonant-phonon structures a value of the electron-lattice energy relaxation rate comparable with that typical of mid-infrared QCLs, in the case of resonant-phonon structures and a value ~ 50 times higher in bound-to-continuum devices.

Paper Details

Date Published: 22 February 2006
PDF: 11 pages
Proc. SPIE 6133, Novel In-Plane Semiconductor Lasers V, 61330K (22 February 2006); doi: 10.1117/12.641467
Show Author Affiliations
Miriam Serena Vitiello, Univ. degli Studi di Bari (Italy)
Gaetano Scamarcio, Univ. degli Studi di Bari (Italy)
Vincenzo Spagnolo, Politecnico di Bari (Italy)
LIT, INFM (Italy)

Published in SPIE Proceedings Vol. 6133:
Novel In-Plane Semiconductor Lasers V
Carmen Mermelstein; David P. Bour, Editor(s)

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