Limiting Factors to the Temperature Performance of THz Quantum Cascade Lasers Based on the Resonant-Phonon Depopulation Scheme
Publication information:
Y. Chassagneux, Q. J. Wang, S. P. Khanna, E. Strupiechonski, J. -R. Coudevylle, E. H. Linfield, A.G. Davies, F. Capasso, M. A. Belkin, and R. Colombelli. 2012. “Limiting Factors to the Temperature Performance of THz Quantum Cascade Lasers Based on the Resonant-Phonon Depopulation Scheme”. IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY, 2, 1, Pp. 83-92. doi:10.1109/TTHZ.2011.2177176
Abstract
We analyze the temperature performance of five terahertz (THz)-frequency quantum cascade lasers based on a three-quantum-well resonant-phonon depopulation design as a function of operating frequency in the 2.3-3.8-THz range. We find evidence that the device performance is limited by the interplay between two factors: 1) optical phonon scattering of thermal electrons, which dominates at shorter wavelengths, and 2) parasitic current, which dominates at longer wavelengths. We present a simple model that provides an accurate estimate of the parasitic current in these devices and predicts the dependence of the threshold current density on temperature.