# US 8,785,905 B1 · Amber light-emitting diode comprising a group III-nitride nanowire active region

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- Number: US 8,785,905 B1
- Document ID: US8785905B1
- Status: Granted
- Kind: B1
- Application number: 13/743,438
- Filed: 2013-01-17
- Granted: 2014-07-22
- Earliest claimed: 2012-01-19
- Assignees: Sandia Corporation
- Applicants: Sandia Corporation
- Inventors: George T. Wang; Qiming Li; Jonathan J. Wierer, Jr.; Daniel Koleske
- Web page: https://patentgrep.com/patent/US8785905B1

## CPC

- H10H 20/811: having quantum effect structures or superlattices, e.g. tunnel junctions
- H10H 20/818: within the light-emitting regions
- H10H 20/821: of the light-emitting regions, e.g. non-planar junctions
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- Y10S 977/762: Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

## Claims

### Claim 1

A light-emitting diode, comprising:
a substrate having a frontside and a backside;
an n-type base grown on the frontside of the substrate;
a core-shell structure on the n-type base, comprising an array of vertically aligned faceted n-type nanowire cores, each core surrounded by a radially grown Group III-nitride multiple quantum well shell layer providing a core-shell nanowire;
a p-type canopy layer grown on all crystal facets of the core-shell nanowires, and that is coalesced at the top providing a continuous top surface, wherein the top surface of the canopy layer is faceted on a plurality of crystal planes of the nanowire cores, thereby providing a continuous film that electrically connects the tops and sides of all the nanowires, further providing a void between adjacent n-type nanowire cores and between the continuous top surface and the n-type base; and
a p-contact to the p-type canopy layer and an n-contact to the n-type base for applying a voltage across the core-shell structure and extracting electroluminescent emitted light therefrom.

### Claim 2 (depends on 1)

The light-emitting diode of claim 1, wherein the n-type nanowire cores comprise n-type GaN, the shell layer comprises an InGaN/GaN multiple quantum well, and the p-type canopy layer comprises p-type InGaN or p-type GaN.

### Claim 3 (depends on 2)

The light-emitting diode of claim 2, wherein the indium concentration of the InGaN layers of the multiple quantum well is greater than 20%.

### Claim 4 (depends on 1)

The light-emitting diode of claim 1, wherein the emitted light has a wavelength of between 550 nm and 620 nm.

### Claim 5 (depends on 1)

The light-emitting diode of claim 1, wherein the p-contact comprises Ni/Au, a transparent conductive oxide, or Ag.

### Claim 6 (depends on 1)

The light-emitting diode of claim 1, wherein the n-contact comprises Al or Ti/Au.

### Claim 7 (depends on 1)

The light-emitting diode of claim 1, wherein the substrate is transparent to the emitted light.

### Claim 8 (depends on 7)

The light-emitting diode of claim 7, wherein the substrate comprises sapphire, silicon, GaN, SiC, or AIN.

### Claim 9 (depends on 7)

The light-emitting diode of claim 7, further comprising a reflective layer deposited on the backside of the substrate.

### Claim 10 (depends on 9)

The light-emitting diode of claim 9, wherein the reflective layer comprises aluminum or silver.

### Claim 11 (depends on 1)

The light-emitting diode of claim 1, further comprising a spreading metal contact layer on the p-type canopy layer.

### Claim 12 (depends on 1)

The light-emitting diode of claim 1, further comprising an indium-tin-oxide layer on the p-type canopy layer.

### Claim 13 (depends on 2)

The light-emitting diode of claim 2, further comprising an InGaN underlayer between the n-type nanowire core and the InGaN/GaN multiple quantum well shell layer.

### Claim 14 (depends on 2)

The light-emitting diode of claim 2, further comprising an AlGaN electron blocking layer between the InGaN/GaN multiple quantum well shell layer and the p-type canopy layer.

### Claim 15 (depends on 1)

The light-emitting diode of claim 1, wherein the height of the nanowire cores is less than 10 microns.

### Claim 16 (depends on 1)

The light-emitting diode of claim 1, wherein the diameter of the nanowire cores is less than 1 micron.

### Claim 17 (depends on 1)

The light-emitting diode of claim 1, wherein the array comprises a hexagonal or rectangular lattice.