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Title: Two-well terahertz quantum cascade lasers with suppressed carrier leakage

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.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [2] ;  [3]
  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)
Publication Date:
Report Number(s):
SAND-2017-8933J
Journal ID: ISSN 0003-6951; 656406
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 111; Journal Issue: 11; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1399568