# US 11,309,473 B2 · Light emitting platform (LEP) with phononic structured nanowires

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- Number: US 11,309,473 B2
- Document ID: US11309473B2
- Status: Granted
- Kind: B2
- Application number: 17/521,104
- Filed: 2021-11-08
- Published: 2022-02-24
- Granted: 2022-04-19
- Earliest claimed: 2016-06-24
- Applicants: William N. Carr
- Inventors: William N. Carr
- Web page: https://patentgrep.com/patent/US11309473B2

## CPC

- G01J 3/108: {for measurement in the infrared range}
- H10H 20/8584: {electrically controlled, e.g. Peltier elements}
- G01J 3/36: Investigating two or more bands of a spectrum by separate detectors
- H10H 29/142: {Two-dimensional arrangements, e.g. asymmetric LED layout}
- G02F 2202/30: Metamaterials
- G02F 2202/32: Photonic crystals
- H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

A semiconductor-based light emitting platform (LEP) comprising a heated blackbody radiator wherein the light emitting platform is thermally isolated by nanowires having ultra-low thermal conductivity. In embodiments, the pixel is structured for broadband emission with a platform comprising an infrared surface structured for high emissivity within a broadband wavelength range. In other embodiments radiation is confined to a limited bandwidth by metamaterial and other resonant filters. In embodiments, the internal efficiency of the LEP configured for broadband operation can be higher compared with an LED.

## Claims

### Claim 1

A light emitting platform (LEP) comprising:
a first substrate having a cavity;
a plurality of nanowires, wherein the nanowires are physically coupled to a microplatform and the first substrate, the nanowires thereby suspending the microplatform in the cavity; wherein the microplatform comprises:
(h) a thermal element and a photonic element;
(i) the photonic element comprises a material or device of increased emissivity for light within a wavelength range;
(j) the thermal element comprises an electric resistive element for heating the microplatform;
(k) at least one of the nanowires comprises a phononic element;
(l) the phononic element includes a crystalline semiconductor first layer comprising structure that reduces a thermal conductivity of the first layer;
(m) the phononic element increases a ratio of electrical conductivity to thermal conductivity of the nanowire; and
the LEP is physically configured for application as a photonic thermal emitter.

### Claim 2 (depends on 1)

The LEP of claim 1 disposed in one or more positions on the first substrate with or without addressing other individual LEPs or other groups of LEPs.

### Claim 3 (depends on 2)

The LEP of claim 2 configured to provide an infrared floodlight or collimated beam spotlight.

### Claim 4 (depends on 2)

The LEP of claim 2 configured wherein individual pixels or groups of pixels are addressable to provide an active infrared signboard.

### Claim 5 (depends on 2)

The LEP of claim 2 configured with the microplatform heated to provide an infrared source for scientific instrumentation applications including spectrophotometry.

### Claim 6 (depends on 2)

The LEP of claim 2 configured for operation within an infrared communication system.

### Claim 7 (depends on 1)

The LEP of claim 1 wherein the thermal element comprises a thermistor or Seebeck thermoelectric junction for sensing temperature of the microplatform.

### Claim 8 (depends on 1)

The LEP of claim 1 wherein the thermal element comprises an electrical resistive heater for gettering the cavity, thereby providing a cleaning function within the cavity.

### Claim 9 (depends on 1)

The LEP of claim 1 wherein the photonic element comprises a material or device of increased emissivity or absorptivity further comprising one or more of nanotubes, graphene, silicon black, gold black, and patterned semiconductor grass providing emissivity within a broadband infrared wavelength range.

### Claim 10 (depends on 1)

The LEP of claim 1 wherein the photonic element comprises an LC inductive-capacitive resonator or a micro-antenna (MA) providing emissivity within a limited infrared wavelength range.

### Claim 11 (depends on 1)

The LEP of claim 1 wherein the photonic element comprises a metamaterial device further comprised of, without limitation, a split ring resonator (SRR), plasmonic patch resonator or Bragg grating (BG) providing emissivity within a limited infrared wavelength range.

### Claim 12 (depends on 1)

The LEP of claim 1 wherein the crystalline first layer comprises phononic resonant and/or phononic non-resonant scattering sites, further wherein scattering sites are separated by less than the mean free path of heat conducting phonons.

### Claim 13 (depends on 1)

The LEP of claim 1 wherein the crystalline first layer comprises phononic crystal (PhC) with structural components disposed in a periodic array, the PhC characterized by a phononic bandgap.

### Claim 14 (depends on 1)

The LEP of claim 1 wherein the crystalline first layer comprises structure increasing nanowire surface roughness, the roughness increasing scattering of heat conducting phonons.

### Claim 15 (depends on 1)

The LEP of claim 1 wherein the crystalline first layer comprises one or more of holes, vias, surface pillars, surface dots, plugs, cavities, local particulates, implanted molecular species and molecular aggregates disposed randomly or in periodic fashion.

### Claim 16 (depends on 1)

The LEP of claim 1 wherein the semiconductor first layer comprises, without limitation, one or more of semiconductors Si, Ge, GaN, SiC and ZnO2.

### Claim 17 (depends on 1)

The LEP of claim 1 wherein the nanowire comprising the nanowire comprising the crystalline first layer is further comprised of an atomic layer deposition (ALD) metal second layer providing an increase in nanowire electrical conductivity.

### Claim 18 (depends on 1)

The LEP of claim 1 wherein the nanowire comprising the crystalline first layer is further comprised of an atomic layer deposition (ALD) dielectric third layer controlling mechanical stress and/or providing electrical isolation.

### Claim 19 (depends on 1)

The LEP of claim 1 wherein the cavity is a hermetic cavity formed by bonding a second substrate onto the first substrate thereby enclosing the platform and nanowires within said cavity.

### Claim 20 (depends on 1)

The LEP of claim 1, wherein the cavity is maintained in a vacuum condition or filled with a gas of decreased thermal conductivity.

### Claim 21 (depends on 1)

The LEP of claim 1, wherein the photonic element comprises a photonic crystal (PC) having phononically-enhanced plasmonic elements coupling into a resonant micro-cavity (RMC) providing infrared emission within a limited wavelength range.