Patent US6534798B1 successfully refreshed from Google Patents.
US6534798B1
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Surface plasmon enhanced light emitting diode and method of operation for the same
Assignee: California Institute of Technology
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Filing: 2000-09-06
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Granted: 2003-03-18
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Expires: 2020-09-06
Abstract
Abstract The emission properties of light-emitting diodes are enhanced by coupling to surface plasmons. The semiconductor emitter layer of the light-emitting diode is thinner than lambd/2 and is sandwiched between two metal films. A periodic pattern is defined in the top semitransparent metal layer by lithography with the result that it efficiently couples out the light emitted from the semiconductor and simultaneously enhances the spontaneous emission rate. Extraction efficiencies of up to 35% and Purcell factors of up to 4.5 are obtainable. Photoluminescence intensities of up to 46 times higher in fabricated structures compared to unprocessed wafers are obtained. The increased light emission is due to an increase in the efficiency and an increase in the pumping intensity resulting from trapping of pump photons within the microcavity.
Inventors
- 👤 Axel Scherer
- 👤 Jelena Vuckovic
- 👤 Marko Loncar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:07
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/862
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
69 words
An improvement in a light emitting diode comprising: an active light emitting semiconductor layer having a first and second parallel surface; an optically reflecting layer disposed on said first surface of said semiconductor layer; and an optically reflecting grating disposed on said second surface of said active light emitting semiconductor layer, said grating having a pattern which is selected so that surface plasmon waves are coupled through said grating.
Claim 2
Dependent Claim
69 words
An improvement in a light emitting diode comprising: an active light emitting semiconductor layer having a first and second parallel surface; an optically reflecting layer disposed on said first surface of said semiconductor layer; and an optically reflecting grating disposed on said second surface of said active light emitting semiconductor layer, said grating having a pattern which is selected so that surface plasmon waves are coupled through said grating.
Claim 3
Dependent Claim
13 words
The improvement of claim 1 wherein said grating has a regular periodic structure.
Claim 4
Dependent Claim
14 words
The improvement of claim 2 where said grating has a one dimensionally periodic structure.
Claim 5
Dependent Claim
14 words
The improvement of claim 2 where said grating has a two dimensionally periodic structure.
Claim 6
Dependent Claim
13 words
The improvement of claim 1 where said optically reflecting grating is partially transparent.
Claim 7
Dependent Claim
18 words
The improvement of claim 1 where optically reflecting layer disposed on said first surface is a conductive layer.
Claim 8
Dependent Claim
18 words
The improvement of claim 1 where optically reflecting grating disposed on said second surface is a conductive layer.
Claim 9
Dependent Claim
16 words
The improvement of claim 1 where said active light emitting semiconductor layer comprises a semiconductor membrane.
Claim 10
Dependent Claim
19 words
The improvement of claim 1 where said active light emitting semiconductor layer comprises a layer including a quantum well.
Claim 11
Dependent Claim
28 words
The improvement of claim 1 where said grating has a selected pattern which is characterized by its coupling to surface plasmons generated by said light emitting semiconductor layer.
Claim 12
Dependent Claim
42 words
The improvement of claim 1 where said light emitting semiconductor layer in combination with said an optically reflecting layer and said an optically reflecting grating comprise a microcavity, said grating characterized by a pattern which couples with surface plasmons in said microcavity.
Claim 13
Dependent Claim
84 words
An improved light emitting diode comprising: an active light emitting semiconductor layer having a first and second parallel and opposing surface; an conductive layer disposed on said first surface of said semiconductor layer; and an conductive grating disposed on said second surface of said active light emitting semiconductor layer, said conductive layer and conductive grating with said semiconductor layer therebetween defining a cavity, said grating having a pattern which is selected so that surface plasmon waves within said cavity are coupled through said grating.
Claim 14
Dependent Claim
84 words
An improved light emitting diode comprising: an active light emitting semiconductor layer having a first and second parallel and opposing surface; an conductive layer disposed on said first surface of said semiconductor layer; and an conductive grating disposed on said second surface of said active light emitting semiconductor layer, said conductive layer and conductive grating with said semiconductor layer therebetween defining a cavity, said grating having a pattern which is selected so that surface plasmon waves within said cavity are coupled through said grating.
Claim 15
Dependent Claim
15 words
The light emitting diode of claim 12 wherein said grating has a regular periodic structure.
Claim 16
Dependent Claim
16 words
The light emitting diode of claim 13 where said grating has a one dimensionally periodic structure.
Claim 17
Dependent Claim
16 words
The light emitting diode of claim 13 where said grating has a two dimensionally periodic structure.
Claim 18
Dependent Claim
13 words
The light emitting diode of claim 12 where said grating is partially transparent.
Claim 19
Independent Claim
87 words
A method of improving emission from a light emitting diode comprising: providing an active light emitting semiconductor layer having a first and second parallel surface; providing an optically reflecting layer disposed on said first surface of said semiconductor layer; providing an optically reflecting grating with a selected pattern defined therein, said grating being disposed on said second surface of said active light emitting semiconductor layer; and coupling surface plasmon waves through said optically reflecting grating, said selected pattern characterized by said surface plasmon waves being coupled therethrough.
Claim 20
Independent Claim
87 words
A method of improving emission from a light emitting diode comprising: providing an active light emitting semiconductor layer having a first and second parallel surface; providing an optically reflecting layer disposed on said first surface of said semiconductor layer; providing an optically reflecting grating with a selected pattern defined therein, said grating being disposed on said second surface of said active light emitting semiconductor layer; and coupling surface plasmon waves through said optically reflecting grating, said selected pattern characterized by said surface plasmon waves being coupled therethrough.
Claim 21
Dependent Claim
24 words
The method of claim 17 where providing an optically reflecting grating with a selected pattern defined therein provides said grating with a periodic pattern.
Claim 22
Dependent Claim
20 words
The method of claim 18 where providing a periodic pattern defined in said grating provides a one dimensional periodic pattern.
Claim 23
Dependent Claim
20 words
The method of claim 18 where providing a periodic pattern defined in said grating provides a two dimensional periodic pattern.
References Cited (Backward Citations)
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