Abstract
We have developed a self-consistent non-equilibrium Green’s function theory (NEGF) for charge transport and optical gain in THz quantum cascade lasers (QCL) and present quantitative results for the I-V characteristics, optical gain, as well as the temperature dependence of the current density for a concrete GaAs/Al.15Ga.85As QCL structure. Phonon scattering, impurity, Hartree electron-electron and interface roughness scattering within the self-consistent Born approximation are taken into account. We show that the characteristic QCL device properties can be successfully modeled by taking into account a single period of the structure, provided the system is consistently treated as open quantum system. In order to support this finding, we have developed two different numerically efficient contact models and compare single-period results with a quasi-periodic NEGF calculation. Both approaches show good agreement with experiment as well as with one another.
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References
Wacker, A.: Gain in quantum cascade lasers and superlattices: a quantum transport theory. Phys. Rev. B 66, 085326 (2002)
Lee, S.-C., Wacker, A.: Nonequilibrium Green’s function theory for transport and gain properties of quantum cascade structures. Phys. Rev. B 66, 245314 (2002)
Lake, R., Klimeck, G., Bowen, R., Jovanovic, D.: Single and multiband modeling of quantum electron transport through layered semiconductor devices. J. Appl. Phys. 81, 7845 (1997)
Iotti, R.C., Rossi, F.: Microscopic modeling of semiconductor-based quantum devices: a predictive simulation strategy. Phys. Stat. Sol. (B) 238, 462 (2003)
Kubis, T., Vogl, P.: Self-consistent quantum transport theory: applications and assessment of approximate models. J. Comput. Electron. 6, 183 (2007)
Svizhenko, A., Anantram, M.P.: Effect of scattering and contacts on current and electrostatics in carbon nanotubes. Phys. Rev. B 72, 085430 (2005)
Benz, A., Fasching, G., Andrews, A.M., Martl, M., Unterrainer, K., Roch, T., Schrenk, W., Golka, S., Strasser, G.: Influence of doping on the performance of terahertz quantum-cascade lasers. Appl. Phys. Lett. 90, 101107 (2007)
Nag, B.R.: Interface roughness scattering limited mobility in AlAs/GaAs, Al.3Ga.7As/GaAs and Ga.5In.5P/GaAs quantum wells. Semicond. Sci. Technol. 19, 162 (2004)
Unuma, T., Yoshita, M., Noda, T., Sakaki, H., Akiyama, H.: Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, alloy disorder, and impurities. J. Appl. Phys. 93, 1586 (2003)
Leosson, K., Jensen, J.R., Langbein, W., Hvam, J.M.: Exciton localization and interface roughness in growth-interrupted GaAs/AlAs quantum wells. Phys. Rev. B 61, 10322 (2000)
Madelung, O., Landolt-Börnstein (eds.): Semiconductors: Intrinsic Properties of Group IV Elements and III-V, II-VI and I-VII Compounds. New Series, Group III/22a. Springer, Berlin (1987)
Kubis, T., Yeh, C., Vogl, P.: Quantum theory of transport and optical gain in quantum cascade lasers. Phys. Stat. Sol. (C) (in press)
Vitiello, M.S., Scamarcio, G., Spagnolo, V., Losco, T., Green, R.P., Tredicucci, A., Beere, H.E., Ritchie, D.A.: Electron-lattice coupling in bound-to-continuum THz quantum-cascade lasers. Appl. Phys. Lett. 88, 241109 (2006)
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Kubis, T., Yeh, C. & Vogl, P. Non-equilibrium quantum transport theory: current and gain in quantum cascade lasers. J Comput Electron 7, 432–435 (2008). https://doi.org/10.1007/s10825-007-0158-2
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DOI: https://doi.org/10.1007/s10825-007-0158-2