# US 10,310,141 B2 · Metamaterial structure and method of fabricating the same

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- Number: US 10,310,141 B2
- Document ID: US10310141B2
- Status: Granted
- Kind: B2
- Application number: 15/671,922
- Filed: 2017-08-08
- Published: 2018-02-15
- Granted: 2019-06-04
- Earliest claimed: 2016-08-09
- Assignees: Electronics and Telecommunications Research Institute; Korea University Research and Business Foundation
- Applicants: Electronics and Telecommunications Research Institute; Korea University Research and Business Foundation
- Inventors: Sunghoon Hong; Heon Lee; Yong Suk Yang; In-Kyu You; Soo-Jung Kim; Hak-Jong Choi
- Web page: https://patentgrep.com/patent/US10310141B2

## CPC

- G02B 1/007: {made of negative effective refractive index materials}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A metamaterial structure may include a first nanoparticle and a second nanoparticle containing a different material from the first nanoparticle. The first and second nanoparticles may be provided to be adjacent to each other and to be in an electrically-coupled state.

## Claims

### Claim 1

A metamaterial structure, comprising:
a substrate; and
patterns provided on the substrate,
wherein the patterns are arranged in a direction parallel to a top surface of the substrate,
each of the patterns comprises a first nanoparticle and a second nanoparticle containing a different material from the first nanoparticle, and
the first and second nanoparticles are provided to be adjacent to each other and to be in an electrically-coupled state.

### Claim 2 (depends on 1)

The metamaterial structure of claim 1, further comprising a conductive ligand coupled to a surface of each of the first and second nanoparticles.

### Claim 3 (depends on 1)

The metamaterial structure of claim 1, wherein a space between the first and second nanoparticles is less than 10 nm.

### Claim 4 (depends on 1)

The metamaterial structure of claim 1, wherein the first and second nanoparticles comprise metal particles that are respectively different from each other.

### Claim 5 (depends on 4)

The metamaterial structure of claim 4, wherein each of the first and second nanoparticles comprises silver (Ag), gold (Au), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), or lead (Pb).

### Claim 6 (depends on 1)

The metamaterial structure of claim 1, wherein the first nanoparticle comprises a metal particle, and
the second nanoparticle comprises a semiconductor particle.

### Claim 7 (depends on 6)

The metamaterial structure of claim 6, wherein the second nanoparticle comprises an elementary semiconductor particle or a compound semiconductor particle.

### Claim 8 (depends on 7)

The metamaterial structure of claim 7, wherein the second nanoparticle comprises CdSe, PbSe, PbS, or PbTe.

### Claim 9 (depends on 1)

The metamaterial structure of claim 1, wherein the first and second nanoparticles are in contact with each other.

### Claim 10 (depends on 1)

The metamaterial structure of claim 1, further comprising a third nanoparticle containing a material different from the first and second nanoparticles,
wherein the first to third nanoparticles are provided to be adjacent to each other and to be in an electrically-coupled state.

### Claim 11 (depends on 10)

The metamaterial structure of claim 10, wherein the third nanoparticle comprises a metal particle or a semiconductor particle.

### Claim 12 (depends on 1)

The metamaterial structure of claim 1, wherein the metamaterial structure has a negative refractive index.

### Claim 13 (depends on 1)

The metamaterial structure of claim 1, wherein each of the patterns has a circular pillar shape.

### Claim 14 (depends on 13)

The metamaterial structure of claim 13, wherein a height and a diameter of each of the patterns range from several nanometers to several hundred micrometers, and
a distance between directly adjacent ones of the patterns ranges from several nanometers to several hundred micrometers.

### Claim 15

A method of fabricating a metamaterial structure, comprising:
providing a substrate;
providing a nanoparticle solution on the substrate, the nanoparticle solution containing a first nanoparticle and a second nanoparticle containing a different material from the first nanoparticle;
exerting pressure on the nanoparticle solution using a stamp; and
curing the nanoparticle solution to form patterns including the first and second nanoparticles,
wherein the first and second nanoparticles are provided to be adjacent to each other and to be in an electrically-coupled state,
the stamp has an uneven surface, and
shapes of the patterns are defined by the uneven surface of the stamp.

### Claim 16 (depends on 15)

The method of claim 15, further comprising sintering the patterns to bring the first and second nanoparticles in contact with each other.

### Claim 17 (depends on 15)

The method of claim 15, wherein each of the first and second nanoparticles comprises a first ligand coupled to a surface thereof,
the method further comprises performing a ligand exchange process on the patterns,
the ligand exchange process is performed to convert the first ligand, which is coupled to each of the first and second nanoparticles, into a second ligand,
a length of the second ligand is shorter than that of the first ligand.

### Claim 18 (depends on 17)

The method of claim 17, wherein the ligand exchange process comprises:
preparing a substitutional solution, in which the second ligand is contained; and
dipping the patterns into the substitutional solution.

### Claim 19 (depends on 17)

The method of claim 17, wherein the second ligand comprises SCN−, I−, Br−, Cl−, or OH−.