Monte Carlo Studies of Intersubband Relaxation in Wide GaAs/AlGaAs Quantum Wells

Dür, Manfred; Goodnick, Stephen M.; Lugli, Paolo

doi:10.1002/1521-3951(199711)204:1<170::aid-pssb170>3.0.co;2-a

Cited by 10 publications

(9 citation statements)

References 7 publications

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“…In the case of the intersubbband relaxation time , the first sum goes over all upper subbands and the second one over all lower subbands in the active region only. Further, the second term in (22) does not contribute to the overall sum because the backward processes are negligible in this case. Screening of the electrons is not involved in both of the rates of (17) and (20) because it is greatly reduced for intersubband scattering [22], especially where the sheet electron densities in the particular subbands are up to 2 10 cm .…”

Section: Electron Relaxation Timesmentioning

confidence: 99%

Self-consistent analysis of carrier transport and carrier capture dynamics in quantum cascade intersubband semiconductor lasers

Kálna

Cheung

Pierce

et al. 1999

Advanced Semiconductor Lasers and Their Applications

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Abstract-A methodology for the self-consistent analysis of carrier transport and carrier capture aspects of the dynamics of quantum cascade intersubband semiconductor lasers is described in this paper. The approach is used to analyze two prototype quantum cascade lasers. The self-consistent analysis incorporates the calculation of the electron densities and temperatures in each subband, together with the intersubband relaxation time. In the calculation of the relaxation time, we take into account the electron interaction with polar optical and acoustic phonons, as well as electron degeneracy. In addition, we also calculate the capture time, considering backward processes that play a role in the electron transition from an injection into an active region. The calculations indicate intersubband relaxation times of order 1 ps and capture times of order 100 fs.

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Section: Electron Relaxation Timesmentioning

confidence: 99%

Self-consistent analysis of carrier transport and carrier capture dynamics in quantum cascade intersubband semiconductor lasers

Kálna

Cheung

Pierce

et al. 1999

Advanced Semiconductor Lasers and Their Applications

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“…One can compare relative importance of e-e and e-imp scattering Dür et al 1996). When we consider intersubband processes, e-imp scattering usually dominates over e-e scattering and significantly increases electron gas heating when final subband after scattering lays lower in energy scale than the starting subband.…”

Section: Electron-impurity Scatteringmentioning

confidence: 99%

Monte Carlo modeling applied to studies of quantum cascade lasers

2017

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One of the commonly used approaches of solving electron transport problems in quantum cascade lasers (QCL) is the Monte Carlo (MC) method, based on semiclassical description in the framework of the Boltzmann Transport Equation. A major benefit of MC modeling is that it only relies on well-established material parameters and structure specification, in most cases without the need to use phenomenological parameters. The results of the modeling can be easily interpreted and they give microscopic insight of QCL operation. The goal of the present paper is to review the application of the MC technique to the studies of operation of QCL. The description of the components of the simulation algorithm is provided. Various physical mechanisms governing electron transport in QCL are described and their influence on the operation are reviewed.

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“…As was the case for carrier-carrier scattering, the two-dimensional integral over u is the Fourier transform of the Coulomb potential [33], and can be solved analytically to give:…”

Section: Impurity Scatteringmentioning

confidence: 99%

Carrier scattering

2016

Quantum Wells, Wires and Dots

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So far, the present work has considered only the static behaviour of carriers in nanostructures. In other words, the states that carriers could occupy within a structure have been calculated, along with the Fermi-Dirac distributions of carriers in thermal equilibrium. However, the equilibrium distribution of carriers is broken in real heterostructure devices (e.g. by the injection of an electric current or an optical 'pump'), and it is therefore important to consider the dynamic behaviour of carriers in such systems in order to predict their distribution accurately.In principle, a complete model of the behaviour of a carrier within a heterostructure could be obtained by finding a Hamiltonian that describes all possible interactions between the carrier and its surroundings, and then solving the time-dependent Schrödinger equation to observe the evolution of the carrier wave function over time. However, this is a formidable computational task, which is further complicated by the random nature of many of the interactions (e.g. randomly distributed impurities). To simplify the problem, carrier dynamics may be approximated by two distinct types of process: coherent processes in which wave functions evolve smoothly between their initial and final states; and incoherent, scattering processes. The latter are the focus of this chapter, and are defined as random, infrequent but very rapid events that transfer a carrier between two states. This could be caused by interactions between carriers and any kind of perturbing potential, including other carriers, impurities, and defects in the heterostructure, or with lattice vibrations (phonons) and photons.Since scattering is assumed to be infrequent, the system can be assumed to stabilise to its static, unperturbed state between events. As such, the eigenstates of the unperturbed system can be calculated (as in Chapters 2 and 3) independently from the scattering dynamics. The very rapid nature of scattering events introduces a further simplification: carriers effectively 'hop' instantaneously from one state to another, and the only necessary task is to compute the rate of scattering (i.e. the number of events per second) for any combination of initial and final states, which is the focus of this chapter. After determining these scattering rates for appropriate interaction processes, the results are used in Chapter 12 to compute the populations of states and current density in devices.

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Monte Carlo Studies of Intersubband Relaxation in Wide GaAs/AlGaAs Quantum Wells

Cited by 10 publications

References 7 publications

Self-consistent analysis of carrier transport and carrier capture dynamics in quantum cascade intersubband semiconductor lasers

Self-consistent analysis of carrier transport and carrier capture dynamics in quantum cascade intersubband semiconductor lasers

Monte Carlo modeling applied to studies of quantum cascade lasers

Carrier scattering

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