GaAs-AlGaAs quantum cascade lasers: physics, technology, and prospects

Sirtori, Carlo; Page, H.; Becker, C.; Ortiz, V.

doi:10.1109/jqe.2002.1005405

Cited by 74 publications

(65 citation statements)

References 41 publications

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“…This is in turn based on a VBO of 0:53x eV, assumed temperature independent, as well as low temperature results for the band gaps of both GaAs and AlAs. This relation for the conduction band offset is however seldom used in the QCL community, 22,25,26 where instead a lower offset is often preferred. This might be more reasonable for the design of structures aimed at high temperature operation, where we expect the band gap to decrease.…”

Section: Model and Estimatesmentioning

confidence: 99%

Simulating terahertz quantum cascade lasers: Trends from samples from different labs

Winge

Franckié

Wacker

2016

Journal of Applied Physics

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We present a systematic comparison of the results from our non-equilibrium Green's function formalism with a large number of AlGaAs-GaAs terahertz quantum cascade lasers previously published in the literature. Employing identical material and simulation parameters for all samples, we observe that discrepancies between measured and calculated peak currents are similar for samples from a given group. This suggests that the differences between experiment and theory are partly due to a lacking reproducibility for devices fabricated at different laboratories. Varying the interface roughness height for different devices, we find that the peak current under lasing operation hardly changes, so that differences in interface quality appear not to be the sole reason for the lacking reproducibility.

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Section: Model and Estimatesmentioning

confidence: 99%

Simulating terahertz quantum cascade lasers: Trends from samples from different labs

Winge

Franckié

Wacker

2016

Journal of Applied Physics

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“…The complex design and operating principle require the technology of quantum cascade lasers to ensure the highest accuracy, uniformity and repeatability of both epitaxy and device processing [6]. High requirements for epitaxy are connected with ultrathin layers of periodic active region, where the wave functions are to be properly engineered [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Mid-Infrared GaAs/AlGaAs Quantum Cascade Lasers Technology

et al. 2009

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“…In previous work on single-stage, unipolar devices RT intersubband emission has been reported only from InP-based structures 2 at a wavelength of 7.7 m. For 30-to 40-stage GaAs-AlGaAs quantum-cascade (QC) lasers at RT, intersubband emission wavelengths shorter than 8 m cannot be achieved, since at higher transition energies the active-region upper level is apparently depopulated via resonant tunneling between the X valleys of the surrounding AlGaAs barriers. 3 We present here the realization of RT mid-IR electroluminescence emission from single-stage intersubband devices. The RT output power is of the same order of magnitude as that of InP-based QC structures of approximately the same wavelength.…”

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confidence: 99%

“…The material used in the devices is grown by lowpressure metalorganic chemical vapor deposition (MOCVD) at 700°C and is essentially a single-stage structure embedded in a plasmon-enhanced n-GaAs waveguide, 3,4 which gives an optical-mode confinement factor, ⌫, of 0.48%. Shown in Fig.…”

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confidence: 99%

“…8 Thus, there is considerably less need for the Bragg mirror/transmitter region characteristic of conventional QC devices. [2][3][4][5][6][7][8] This fact, aside from meaning less device complexity and easier fabrication, allows for the fabrication of QC devices for which backfilling 1,7 becomes negligible at room temperature 9 (e.g., if two structures similar to the one shown in Fig. 1 are placed FIG.…”

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Room-temperature, mid-infrared (λ=4.7μm) electroluminescence from single-stage intersubband GaAs-based edge emitters

Duan

Mirabedini

D'Souza

et al. 2004

Applied Physics Letters

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GaAs-based, single-stage, intersubband devices with active regions composed of deep quantum wells (i.e., In 0.3 Ga 0.7 As) and high AlGaAs barriers display strong room-temperature emission at = 4.7 m. The structures are grown by metalorganic chemical vapor deposition. The large energy barriers ͑ϳ360 meV͒ for electrons in the upper energy level of the active region strongly suppress both the carrier leakage as well as the tunneling escape rate out of the wells. As a result, the ratio of emissions at 80 and 300 K is as low as 2.0, and thus there is considerably less need for a Bragg mirror/transmitter-type region. Devices with virtually 100% tunneling injection efficiency have been realized, and their room-temperature spectra are narrow: 25 meV full width at half maximum. In the quest to achieve efficient, room-temperature (RT), continuous-wave (cw) laser operation in the mid-infrared (IR) wavelength range (i.e., 3 -5 m) one proposed approach is the use of two-dimensional arrays of unipolar quantum boxes 1 (QBs), with each QB incorporating a singlestage, intersubband-transition structure. In previous work on single-stage, unipolar devices RT intersubband emission has been reported only from InP-based structures 2 at a wavelength of 7.7 m. For 30-to 40-stage GaAs-AlGaAs quantum-cascade (QC) lasers at RT, intersubband emission wavelengths shorter than 8 m cannot be achieved, since at higher transition energies the active-region upper level is apparently depopulated via resonant tunneling between the X valleys of the surrounding AlGaAs barriers. 3 We present here the realization of RT mid-IR electroluminescence emission from single-stage intersubband devices. The RT output power is of the same order of magnitude as that of InP-based QC structures of approximately the same wavelength. The RT emission linewidth is narrow [ϳ25 meV full width at half maximum (FWHM)] and the 80" 300 K emission ratio is very low ͑ϳ2͒.Optimization studies of GaAs-based devices 4 have shown that for thin barriers between the injector region and the active region, two effects occur which cause significant decreases in the upper-(energy) state injection efficiency: (1) a diagonal radiative transition from the injector-region ground state, g, to an active-region lower state, and (2) severe carrier leakage from the state g to the continuum. Here we show that by using GaAs-based devices with very deep active quantum wells (QWs), In 0.3 Ga 0.7 As active layers sandwiched between Al 0.8 Ga 0.2 As barriers, we can virtually suppress carrier leakage to the continuum. Furthermore, since GaAs/ AlGaAs superlattices do not need to be used on both sides of the active region, resonant tunneling cannot occur between X valleys at high transition energies, and thus RT emission in the mid-IR range becomes possible for GaAs-based devices.The material used in the devices is grown by lowpressure metalorganic chemical vapor deposition (MOCVD) at 700°C and is essentially a single-stage structure embedded in a plasmon-enhanced n-GaAs waveguide, 3,4 which gives an op...

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GaAs-AlGaAs quantum cascade lasers: physics, technology, and prospects

Cited by 74 publications

References 41 publications

Simulating terahertz quantum cascade lasers: Trends from samples from different labs

Simulating terahertz quantum cascade lasers: Trends from samples from different labs

Mid-Infrared GaAs/AlGaAs Quantum Cascade Lasers Technology

Room-temperature, mid-infrared (λ=4.7μm) electroluminescence from single-stage intersubband GaAs-based edge emitters

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