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Conference Paper: Broadband emission from an ensemble of nano-pillars with multiple diameters
Title | Broadband emission from an ensemble of nano-pillars with multiple diameters |
---|---|
Authors | |
Issue Date | 2013 |
Publisher | OPTO SPIE Photonics West. |
Citation | The 2013 OPTO SPIE Photonics West Conference, San Francisco, CA., 2-7 February 2013. In Technical Abstracts: OPTO, 2013, p. 314, abstract no. 8641-63, Session 4 How to Cite? |
Abstract | Generating white light from monochromatic light sources is commonly
achieved via one of two common methods: exciting fluorescence
phosphors from a shorter wavelength LED, or mixing light from three or
more LED chips, commonly known as RGB LEDs. Phosphor efficiency
degrade over time, and have lifetimes shorter than the chip itself. RGB
LEDs require turning on three or more p-n junctions and suffer from color
mixing issues. We introduce a promising approach towards achieving
phosphor-free white light emission, tapping on strain engineering and
nanoscale processing.
The proposed approach makes use of a long wavelength chip, which is
invariably strained due to the high Indium content. By relaxing the built-in
strain in a controllable manner, through the formation of dimension and
site-controlled nano-pillars, the emission wavelength of individual pillars
of varying sizes will blue-shift towards short wavelengths. The extent of
blue-shift (strain relaxation) depends on a number of factors including
dimension and lateral ion penetration.
Nano-pillars of a continuum of dimensions are patterned by nanosphere
lithography, making use of a nanosphere colloid containing spheres with
a wide range of diameters. The resultant structure contains an ensemble
of nano-pillars each emitting a slighting different wavelength according
to its dimension, producing a continuous broadband spectrum with
FWHM of 72.23nm. With the right mix of nano-pillar dimensions, different
shades of white light can be generated from a single array, representing
a viable single-chip phosphor-free white light generating solution. Most
importantly, the strain-relaxed nanostructures offer both high internal
quantum efficiencies and light extraction efficiencies. |
Description | Conference 8641: Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting 17 The Conference program's website is located at http://spie.org/x92791.xml |
Persistent Identifier | http://hdl.handle.net/10722/204040 |
DC Field | Value | Language |
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dc.contributor.author | Li, KH | - |
dc.contributor.author | Choi, HW | - |
dc.date.accessioned | 2014-09-19T20:02:02Z | - |
dc.date.available | 2014-09-19T20:02:02Z | - |
dc.date.issued | 2013 | - |
dc.identifier.citation | The 2013 OPTO SPIE Photonics West Conference, San Francisco, CA., 2-7 February 2013. In Technical Abstracts: OPTO, 2013, p. 314, abstract no. 8641-63, Session 4 | - |
dc.identifier.uri | http://hdl.handle.net/10722/204040 | - |
dc.description | Conference 8641: Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting 17 | - |
dc.description | The Conference program's website is located at http://spie.org/x92791.xml | - |
dc.description.abstract | Generating white light from monochromatic light sources is commonly achieved via one of two common methods: exciting fluorescence phosphors from a shorter wavelength LED, or mixing light from three or more LED chips, commonly known as RGB LEDs. Phosphor efficiency degrade over time, and have lifetimes shorter than the chip itself. RGB LEDs require turning on three or more p-n junctions and suffer from color mixing issues. We introduce a promising approach towards achieving phosphor-free white light emission, tapping on strain engineering and nanoscale processing. The proposed approach makes use of a long wavelength chip, which is invariably strained due to the high Indium content. By relaxing the built-in strain in a controllable manner, through the formation of dimension and site-controlled nano-pillars, the emission wavelength of individual pillars of varying sizes will blue-shift towards short wavelengths. The extent of blue-shift (strain relaxation) depends on a number of factors including dimension and lateral ion penetration. Nano-pillars of a continuum of dimensions are patterned by nanosphere lithography, making use of a nanosphere colloid containing spheres with a wide range of diameters. The resultant structure contains an ensemble of nano-pillars each emitting a slighting different wavelength according to its dimension, producing a continuous broadband spectrum with FWHM of 72.23nm. With the right mix of nano-pillar dimensions, different shades of white light can be generated from a single array, representing a viable single-chip phosphor-free white light generating solution. Most importantly, the strain-relaxed nanostructures offer both high internal quantum efficiencies and light extraction efficiencies. | - |
dc.language | eng | - |
dc.publisher | OPTO SPIE Photonics West. | - |
dc.relation.ispartof | OPTO SPIE Photonics West Conference | - |
dc.title | Broadband emission from an ensemble of nano-pillars with multiple diameters | - |
dc.type | Conference_Paper | - |
dc.identifier.email | Li, KH: khei@eee.hku.hk | - |
dc.identifier.email | Choi, HW: hwchoi@hku.hk | - |
dc.identifier.authority | Choi, HW=rp00108 | - |
dc.identifier.hkuros | 236788 | - |
dc.identifier.spage | 314, abstract no. 8641-63, Session 4 | - |
dc.identifier.epage | 314, abstract no. 8641-63, Session 4 | - |
dc.publisher.place | United States | - |