Nonequilibrium Green's function theory for transport and gain properties of quantum cascade structures

Abstract

The transport and gain properties of quantum cascade (QC) structures are investigated using a nonequilibrium Green's function (NGF) theory which includes quantum effects beyond a Boltzmann transport description. In the NGF theory, we include interface roughness, impurity, and electron-phonon scattering processes within a self-consistent Born approximation, and electron-electron scattering in a mean-field approximation. With this theory we obtain a description of the nonequilibrium stationary state of QC structures under an applied bias, and hence we determine transport properties, such as the current-voltage characteristic of these structures. We define two contributions to the current, one contribution driven by the scattering-free part of the Hamiltonian, and the other driven by the scattering Hamiltonian. We find that the dominant part of the current in these structures, in contrast to simple superlattice structures, is governed mainly by the scattering Hamiltonian. In addition, by considering the linear response of the stationary state of the structure to an applied optical field, we determine the linear susceptibility, and hence the gain or absorption spectra of the structure. A comparison of the spectra obtained from the more rigorous NGF theory with simpler models shows that the spectra tend to be offset to higher values in the simpler theories.

44 pages, 16 figures, appearing in Physical Review B Dec 2002

References in corpus (8)

• Semiconductor Superlattices: A model system for nonlinear transport
• Wannier-Stark resonances in optical and semiconductor superlattices
• On the Nature of Charge Transport in Quantum-Cascade Lasers
• Gain in quantum cascade lasers and superlattices: A quantum transport theory
• Impurity bands and sequential resonant tunneling in the presence of terahertz fields
• Sequential tunneling in doped superlattices: Fingerprints of impurity bands and photon-assisted tunneling
• Quantum transport calculations for quantum cascade laser structures
• Gain and Loss in Quantum Cascade Lasers

Cited by in corpus (42)

• Modeling techniques for quantum cascade lasers
• Coherence of resonant-tunneling transport in terahertz quantum-cascade lasers
• Quantum-mechanical wavepacket transport in quantum cascade laser structures
• Microscopic non-equilibrium theory of quantum well solar cells
• Self-Consistent Theory of the Gain Linewidth for Quantum Cascade Lasers
• Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism
• Temperature dependence of the gain profile for THz quantum cascade lasers
• A phonon scattering assisted injection and extraction based terahertz quantum cascade laser
• Density-matrix theory of the optical dynamics and transport in quantum cascade structures: The role of coherence
• Electron transport in quantum wire superlattices
• Contrasting influence of charged impurities on transport and gain in terahertz quantum cascade lasers
• Room temperature operation of n-type Ge/SiGe terahertz quantum cascade lasers predicted by non-equilibrium Green's functions
• Controlling many-body effects in the midinfrared gain and THz absorption of quantum cascade laser structures
• Density matrix theory of transport and gain in quantum cascade lasers in a magnetic field
• Non-equilibrium Green's function predictions of band tails and band gap narrowing in III-V semiconductors and nanodevices
• Extraction-Controlled Quantum Cascade Lasers
• Coherence and Spatial Resolution of Transport in Quantum Cascade Lasers
• Fingerprints of spatial charge transfer in Quantum Cascade Lasers
• Quantum transport in semiconductor quantum dot superlattices: electron-phonon resonances and polaron effects
• Density Matrix Modeling of Quantum Cascade Lasers without an Artificially Localized Basis: A Generalized Scattering Approach
• Theoretical analysis of spectral gain in a THz quantum cascade laser: prospects for gain at 1 THz
• Nanowire terahertz quantum cascade lasers
• Material configurations for n-type silicon-based terahertz quantum cascade lasers
• Theory and design of quantum cascade lasers in (111) n-type Si/SiGe
• Effective microscopic theory of quantum dot superlattice solar cells
• Nonlinear response of quantum cascade structures
• Simulating terahertz quantum cascade lasers: Trends from samples from different labs
• Quantum transport in weakly coupled superlattices at low temperature
• Nonequilibrium thermodynamics of interacting tunneling transport: variational grand potential, density-functional formulation, and nature of steady-state forces
• Band tail formation in mono and multilayered transition metal dichalcogenides: A detailed assessment and a quick-reference guide
• Nonequilibrium theory of the conversion-efficiency limit of solar cells including thermalization and extraction of carriers
• Three-Dimensional Interface Roughness in Layered Semiconductor Structures and Its Effects on Intersubband Transitions
• Density-functional theory of nonequilibrium tunneling
• Quantum-kinetic perspective on photovoltaic device operation in nanostructure-based solar cells
• Density-matrix model for photon-driven transport in quantum cascade lasers
• Anomalous transport in a topological Wannier-Stark ladder
• Potential-inserted quantum well design for quantum cascade terahertz lasers
• Magnetotunnelling in resonant tunnelling structures with spin-orbit interaction
• Partially coherent electron transport in terahertz quantum cascade lasers based on a Markovian master equation for the density matrix
• Orthonormal and periodic levels for Quantum Cascade Laser simulation
• Numerically efficient density-matrix technique for modeling electronic transport in midinfrared quantum cascade lasers
• Transport Electronique Dans Les Super Reseaux : Applications Aux Détecteurs Infrarouges à Grandes Longueur D'onde