Two-well terahertz quantum cascade lasers with suppressed carrier leakage

Journal Article · 10 September 2017 · Applied Physics Letters

DOI: https://doi.org/10.1063/1.4996567 · OSTI ID:1399568

Albo, Asaf  ^[1]; Flores, Yuri V.  ^[2]; Hu, Qing ^[2]; Reno, John L. ^[3]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Bar-Ilan Univ., Ramat Gan (Israel)
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

The mechanisms that limit the temperature performance of diagonal GaAs/Al_0.15GaAs_0.85-based terahertz quantum cascade lasers (THz-QCLs) have been identified as thermally activated leakage of charge carriers through excited states into the continuum. THz-QCLs with energetically higher-laying excited states supported by sufficiently high barriers aim to eliminate these leakage mechanisms and lead to improved temperature performance. Although suppression of thermally activated carrier leakage was realized in a three-well THz-QCL based on a resonant-phonon scheme, no improvement in the temperature performance was reported thus far. Here, we report a major improvement in the temperature performance of a two-quantum-well direct-phonon THz-QCL structure. We show that the improved laser performance is due to the suppression of the thermally activated carrier leakage into the continuum with the increase in the injection barrier height. Furthermore, we demonstrate that high-barrier two-well structures can support a clean three-level laser system at elevated temperatures, which opens the opportunity to achieve temperature performance beyond the state-of-the-art.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1399568
• Report Number(s): SAND--2017-8933J; 656406
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 11 Vol. 111; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English