1. High-Power Growth-Robust InGaAs/InAlAs Terahertz Quantum Cascade Lasers
- Author
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Deutsch, Christoph, Kainz, Martin Alexander, Krall, Michael, Brandstetter, Martin, Bachmann, Dominic, Schönhuber, Sebastian, Detz, Hermann, Zederbauer, Tobias, MacFarland, Donald, Andrews, Aaron Maxwell, Schrenk, Werner, Beck, Mattias, Ohtani, Keita, Faist, Jérôme, Strasser, Gottfried, and Unterrainer, Karl
- Subjects
terahertz ,low effective mass ,quantum cascade lasers ,molecular beam epitaxy ,nanostructures ,quantized transitions ,Article - Abstract
We report on high-power terahertz quantum cascade lasers based on low effective electron mass InGaAs/InAlAs semiconductor heterostructures with excellent reproducibility. Growth-related asymmetries in the form of interface roughness and dopant migration play a crucial role in this material system. These bias polarity dependent phenomena are studied using a nominally symmetric active region resulting in a preferential electron transport in the growth direction. A structure based on a three-well optical phonon depletion scheme was optimized for this bias direction. Depending on the sheet doping density, the performance of this structure shows a trade-off between high maximum operating temperature and high output power. While the highest operating temperature of 155 K is observed for a moderate sheet doping density of 2 × 1010 cm–2, the highest peak output power of 151 mW is found for 7.3 × 1010 cm–2. Furthermore, by abutting a hyperhemispherical GaAs lens to a device with the highest doping level a record output power of 587 mW is achieved for double-metal waveguide structures.
- Published
- 2017