InGaAs/GaAsSb/InP terahertz quantum cascade lasers

Deutsch, C.; Detz, Hermann; Zederbauer, Tobias; Krall, Michael; Brandstetter, Markus; Andrews, A. M.; Klang, P.; Schrenk, W.; Strasser, G.; Unterrainer, K.

doi:10.1007/s10762-013-9991-5

Cited by 11 publications

(4 citation statements)

References 45 publications

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“…This can probably be attributed to the higher growth rates used for In 0.53 Ga 0.47 As‐based structures. Although dopant migration is also present in In 0.53 Ga 0.47 As/GaAs 0.51 Sb 0.49 structures, these can not directly be compared as the ratio of threshold current densities is dominated by interface roughness scattering …”

Section: Growth Optimizationmentioning

confidence: 99%

Evaluation of Material Systems for THz Quantum Cascade Laser Active Regions

Detz

Andrews

Kainz

et al. 2018

Phys. Status Solidi A

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Quantum cascade lasers (QCLs) have been realized in several different material systems. In the mid-infrared, active regions are predominantly based on In 0.53 Ga 0.47 As and InAs as quantum well material. Market-ready devices routinely provide continuous-wave operation at room temperature. For their THz counterparts, the situation is less clear. The most common material system for THz QCLs is the inherently lattice-matched combination of GaAs with Al 0.15 Ga 0.85 As barriers. Yet, these devices still only reach a maximum operating temperature of 200 K with a lack of progress within the past years. Based on the identification of key parameters, this work reviews material systems for quantum cascade lasers with an emphasis on material and growth-related aspects and the goal to identify promising candidates for future device generations. Similar active regions realized in different material systems allow to estimate the gain per unit thickness, as well as total growth times and relative thickness errors.

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Section: Growth Optimizationmentioning

confidence: 99%

Evaluation of Material Systems for THz Quantum Cascade Laser Active Regions

Detz

Andrews

Kainz

et al. 2018

Phys. Status Solidi A

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“…Terahertz QCLs with the best performance are realized with one-dimensional GaAs/AlGaAs superlattices due to maturity of the growth technology and superior material quality of the grown superlattices. Research and development in other material systems such as InGaAs/InAlAs [32,33] and InGaAs/GaAsSb [34] is ongoing owing to the lower effective mass of electrons that is perceived to be attractive for realization of larger intersubband gain for comparable design parameters of a given QCL design. Efforts are also ongoing to shrink the physical dimensions of the active region for additional carrier quantum confinement in terahertz QCLs by making micropillars [35] and nanopillars [36], which has the potential to mitigate undesired nonradiative scattering channels and enhance intersubband gain in terahertz QCLs at higher temperatures.…”

Section: Existing Terahertz Qclsmentioning

confidence: 99%

Temperature performance of terahertz quantum-cascade lasers with resonant-phonon active-regions

Khanal

Zhao

Reno

et al. 2014

J. Opt.

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Significant progress has recently been made toward improving the power output, beam quality and spectral characteristics of terahertz quantum cascade lasers (QCLs). However, the maximum operating temperature of the best-performing devices has become relatively stagnant and is in the range of 150-200 K for QCLs designed to emit in the frequency range of 2-4 THz. Such QCLs are primarily designed with resonant-phonon depopulation schemes. The requirement to cryogenically cool terahertz QCLs leads to stringent limitations on their use for various applications. Although significant advances have been made to model quantum transport in quantum cascade superlattices, the relative role of various electron transport mechanisms as a function of temperature is not clear. This article discusses temperature behavior of resonantphonon terahertz QCLs with respect to a variety of active-region design schemes, and argues that precise understanding of high-temperature transport remains elusive for terahertz QCLs. The role of electron-phonon scattering, collisional-broadening, thermal leakage, and interface-roughness scattering towards the degradation of intersubband optical gain at higher temperatures is discussed for the popular terahertz QCL designs.

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“…The latter requires very thin layers of InAlAs and is therefore difficult to manufacture epitaxially [1]. One solution to overcome this issue, while still making use of the benefits provided by InGaAs, namely lower effective electron mass (m*= 0.043m0) which leads to a higher optical gain, is the usage of different barrier materials such as the ternary GaAsSb [2] and the quaternary InAlGaAs [3]. Crucial for the barrier thickness is the conduction band offset (CBO) of the material system.…”

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confidence: 99%