Lasing properties of GaAs/(Al,Ga)As quantum-cascade lasers as a function of injector doping density

Giehler, M.; Hey, R.; Kostial, H.; Cronenberg, Sven; Ohtsuka, T.; Schrottke, L.; Grahn, H. T.

doi:10.1063/1.1541099

Cited by 46 publications

(36 citation statements)

References 14 publications

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“…40,41 The doping level in the active region is an important parameter with particular influence on the dynamic working range of QCLs. Until now, very few experimental investigations have been presented including the influence of the injector doping on InP-based [42][43][44] and GaAs-based [45][46][47][48] QCL threshold currents.…”

Section: Introductionmentioning

confidence: 99%

Influence of doping density on electron dynamics in GaAs∕AlGaAs quantum cascade lasers

Jovanović

Höfling

Indjin

et al. 2006

Journal of Applied Physics

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A detailed theoretical and experimental study of the influence of injector doping on the output characteristics and electron heating in midinfrared GaAs/ AlGaAs quantum cascade lasers is presented. The employed theoretical model of electron transport was based on a fully nonequilibrium self-consistent Schrödinger-Poisson analysis of the scattering rate and energy balance equations. Three different devices with injector sheet doping densities in the range of ͑4 -6.5͒ ϫ 10 11 cm -2 have been grown and experimentally characterized. Optimized arsenic fluxes were used for the growth, resulting in high-quality layers with smooth surfaces and low defect densities. A quasilinear increase of the threshold current with sheet injector doping has been observed both theoretically and experimentally. The experimental and calculated current-voltage characteristics are in a very good agreement. A decrease of the calculated coupling constant of average electron temperature versus the pumping current with doping level was found.

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Section: Introductionmentioning

confidence: 99%

Influence of doping density on electron dynamics in GaAs∕AlGaAs quantum cascade lasers

Jovanović

Höfling

Indjin

et al. 2006

Journal of Applied Physics

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“…Although the corrections are small it is interesting to note that Coulomb corrections lead to smaller increase in peak gain position on the high density, making the results slightly closer, qualitatively, to the experimental findings of Ref. [16]. However, Coulomb effects only are not enough to explain their results and a more detailed analysis is required.…”

Section: Numerical Results and Discussionmentioning

confidence: 75%

“…In order to keep our discussion as close as possible to experimental realizations, we chose densities and temperatures compatible with the samples described in Refs. [15,16]. Figure 5 shows the absorption spectra with and without Hartree-Fock Coulomb corrections for different doping densities.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

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Controlling many-body effects in the midinfrared gain and terahertz absorption of quantum cascade laser structures

2004

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A many-body theory based on nonequilibrium Green functions, in which transport and optics are treated on a microscopic quantum mechanical basis, is used to compute gain and absorption in the optical and THz regimes in quantum cascade laser structures. The relative importance of Coulomb interactions for different intersubband transitions depends strongly on the spatial overlap of the wavefunctions and the specific nonequilibrium populations within the subbands. The magnitude of the Coulomb effects can be controlled by changing the operation bias.

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“…Until now, very few experimental investigations have been presented that have discussed the influence of the injector doping on QCL threshold currents. [17][18][19] In this work we report on such a theoretical investigation of a recent four-quantum-well design, 9 in which the influence of the injector doping density on the electron dynamics and on the carrier heating is analyzed.…”

Section: Introductionmentioning

confidence: 99%

Aspects of the internal physics of InGaAs∕InAlAs quantum cascade lasers

Tavish

Indjin

Harrison

2006

Journal of Applied Physics

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We report on the results of our simulations of an InGaAs/ InAlAs midinfrared quantum cascade laser ͑QCL͒ designed to operate in continuous wave mode at room temperature ͓Beck et al., Science 295, 301 ͑2002͔͒. Our physical model of the device consists of a self-consistent solution of the subband population rate equations and accounts for all electron-longitudinal-optical phonon and electron-electron scattering rates, as well as an evaluation of the temperature of the nonequilibrium electron distribution. We also consider the role of the doping density and its influence on the electron dynamics. We found that the temperature of the nonequilibrium electron distribution differed significantly from the lattice temperature and that this temperature increased with applied electric field and current density, with coupling constants somewhat larger than analogous GaAs based midinfrared QCLs. Our simulations also reveal physical processes of the device that are not apparent from the experimental measurements, such as the role of electron-electron scattering.

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Lasing properties of GaAs/(Al,Ga)As quantum-cascade lasers as a function of injector doping density

Cited by 46 publications

References 14 publications

Influence of doping density on electron dynamics in GaAs∕AlGaAs quantum cascade lasers

Influence of doping density on electron dynamics in GaAs∕AlGaAs quantum cascade lasers

Controlling many-body effects in the midinfrared gain and terahertz absorption of quantum cascade laser structures

Aspects of the internal physics of InGaAs∕InAlAs quantum cascade lasers

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