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Proceedings Paper

Optical properties and electronic requirements for low-temperature operation of yellow semiconductor LEDs
Author(s): Susanne M. Lee; Eduard K. Mueller; Brian C. Van de Workeen; Otward M. Mueller
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Paper Abstract

In such LED applications as lighting, it is desirable to have the highest light output for the lowest power consumption. This paper investigates the optical properties and electronic requirements of a commercially available yellow LED as a function of temperature from ambient to liquid nitrogen temperatures. It was found that the illuminance increased by almost an order of magnitude, producing much higher light output at the same diode current. However, the operating voltage increased, increasing the overall power consumption slightly. The efficiency (light-watt output to electrical watts consumed) of the LED, though, improved by a factor of more than three. This, combined with the enhanced light output, compensates for the small increase in power consumption and added cooling costs. These improvements further translate into a comparable increase in the lifetime of the LEDs. In general, each ten-degree reduction in temperature corresponds to a doubling of the lifetime of semiconductor devices. It was also found that the maximum operating current increased significantly at liquid nitrogen temperatures over that at ambient temperatures. Lastly, the emitted wavelength range shifted to shorter values in addition to the significant increase in brightness. Thus, a yellow- colored LED at room temperature gave off a much brighter yellow-green-white color at liquid nitrogen temperatures.

Paper Details

Date Published: 14 May 2001
PDF: 10 pages
Proc. SPIE 4278, Light-Emitting Diodes: Research, Manufacturing, and Applications V, (14 May 2001); doi: 10.1117/12.426853
Show Author Affiliations
Susanne M. Lee, SUNY/Albany (United States)
Eduard K. Mueller, SUNY/Albany and Low Temperature Electronics (United States)
Brian C. Van de Workeen, SUNY/Albany (United States)
Otward M. Mueller, Low Temperature Electronics (United States)

Published in SPIE Proceedings Vol. 4278:
Light-Emitting Diodes: Research, Manufacturing, and Applications V
H. Walter Yao; E. Fred Schubert, Editor(s)

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