6 October 2006 Free carrier screening in coupled asymmetric GaN quantum discs
Author Affiliations +
Proceedings Volume 6352, Optoelectronic Materials and Devices; 635214 (2006) https://doi.org/10.1117/12.689176
Event: Asia-Pacific Optical Communications, 2006, Gwangju, South Korea
We present an investigation of free-carrier screening in coupled asymmetric GaN quantum discs with embedded AlGaN barriers using time-integrated and time-resolved micro-photoluminescence measurements, supported by three-dimensional multi-band k.p computational modeling. We observe that with increasing optical excitation the carrier lifetime decreases and emission energy blue-shifts. This originates from the screening of built-in piezo- and pyroelectric fields in the quantum discs by photo-generated free-carriers. Due to non-resonant tunneling of carriers from the smaller disc to the larger disc, free carrier screening is enhanced in the larger disc. The non-resonant tunneling was found to have a significant role in samples with a thin barrier, as the screening decreased with barrier thickness (i.e. decreased tunneling). Computational modeling was in good agreement with the experimental results.
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K. H. Lee, K. H. Lee, J. H. Na, J. H. Na, S. Birner, S. Birner, R. A. Taylor, R. A. Taylor, S. N. Yi, S. N. Yi, Y. S. Park, Y. S. Park, C. M. Park, C. M. Park, T. W. Kang, T. W. Kang, "Free carrier screening in coupled asymmetric GaN quantum discs", Proc. SPIE 6352, Optoelectronic Materials and Devices, 635214 (6 October 2006); doi: 10.1117/12.689176; https://doi.org/10.1117/12.689176

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