High Efficiency LEDs
The smallest optical
cavities can be constructed at length-scales far below
the wavelength of
light – by using surface plasmons formed at the surfaces of metallic
nanostructures. These surface plasmons can also be used to efficiently
extract light from light emitting diodes. We show in the Nature
Materials paper entitled “Surface-plasmon-enhanced
light emitters based on InGaN quantum wells” that it is
possible to improve both internal and external quantum efficiencies of
light emitting diode material by using metallic nanostructures. As a
result, depositing metallic layers onto InGaN provides a 14-fold
increase in the luminescence intensity, and leads to the opportunity of
developing highly efficient light emitting diodes.
Moreover, the
modulation frequency of the resulting light
emitting devices is
increased by a similar factor. This work resulted from
several years of
research in high-efficiency light emitting diodes, with external quantum
efficiencies of over 30% derived from surface patterning of the light
emitting diode.
