Temperature characteristics of light emission spectra and threshold currents of columnar-shaped self-assembled InGaAs/GaAs quantum-dot lasers

Mitsuru Sugawara; Kohki Mukai; Yoshiaki Nakata

doi:10.1117/12.344521

1 April 1999 Temperature characteristics of light emission spectra and threshold currents of columnar-shaped self-assembled InGaAs/GaAs quantum-dot lasers

Mitsuru Sugawara, Kohki Mukai, Yoshiaki Nakata

Author Affiliations +

Proceedings Volume 3628, In-Plane Semiconductor Lasers III; (1999) https://doi.org/10.1117/12.344521
Event: Optoelectronics '99 - Integrated Optoelectronic Devices, 1999, San Jose, CA, United States

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.

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Mitsuru Sugawara, Kohki Mukai, and Yoshiaki Nakata "Temperature characteristics of light emission spectra and threshold currents of columnar-shaped self-assembled InGaAs/GaAs quantum-dot lasers", Proc. SPIE 3628, In-Plane Semiconductor Lasers III, (1 April 1999); https://doi.org/10.1117/12.344521

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