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Proceedings Paper

Temperature characteristics of light emission spectra and threshold currents of columnar-shaped self-assembled InGaAs/GaAs quantum-dot lasers
Author(s): Mitsuru Sugawara; Kohki Mukai; Yoshiaki Nakata
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Paper Abstract

We examined the temperature characteristics of light emission spectra and threshold currents for columnar-shaped self- assembled InGaAs quantum dot lasers which show lasing from the ground-state quantized level. While lasing occurred with one line including a series of longitudinal modes at room temperature, spectra at 80 K showed broad lasing emission over a range of 50 - 60 meV. We explain this result by a model that dots with different energies start lasing independently at low temperatures due to their spatial localization, while at room temperature the dots contribute to one-line lasing collectively via homogeneous broadening of optical gain. We attribute the origin of homogeneous broadening to scattering processes to exchange carriers between the ground state and excited states. The characteristic temperature of threshold currents was T0 equals 60 - 90 K between 287 K and 353 K. By evaluating the current dependence of the spontaneous emission spectra up to lasing thresholds at various temperatures, we found that this low T0 is due to the increase in the nonradiative current component, presumably caused by nonradiative carrier recombination through defects in the wetting layer. These results show the importance of controlling carrier distribution in the excited states including the wetting layer to achieve high-performance quantum-dot lasers.

Paper Details

Date Published: 1 April 1999
PDF: 8 pages
Proc. SPIE 3628, In-Plane Semiconductor Lasers III, (1 April 1999); doi: 10.1117/12.344521
Show Author Affiliations
Mitsuru Sugawara, Fujitsu Labs. Ltd. (Japan)
Kohki Mukai, Fujitsu Labs. Ltd. (Japan)
Yoshiaki Nakata, Fujitsu Labs. Ltd. (Japan)


Published in SPIE Proceedings Vol. 3628:
In-Plane Semiconductor Lasers III
Hong K. Choi; Peter S. Zory, Editor(s)

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