Optical device and a method of fabricating an optical device

Patent metadata

Field	Value
Publication number	US-2016240728-A1
Application number	US-201514861497-A
Country	US
Kind code	A1
Filing date	Sep 22, 2015
Priority date	Feb 12, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

An optical device comprising: a photonic crystal structure, comprising: a layer of a first material, the layer comprising a quantum emitter; and a plurality of regions of a second material in the layer of the first material, the regions arranged in a regular lattice having at least one region missing from the lattice so that a defect is formed, wherein the quantum emitter is located in the defect part of the photonic crystal structure; wherein the second material has a different refractive index to the first material; and an electrode which is electrically contacted to only the defect part of the photonic crystal structure.

First claim

1 . An optical device, comprising:
a photonic crystal structure, comprising:
a layer of a first material, the layer comprising a quantum emitter; and
a plurality of regions of a second material in the layer of the first material, the regions arranged in a regular lattice having at least one region missing from the lattice so that a defect is formed, wherein the quantum emitter is located in the defect part of the photonic crystal structure;
wherein the second material has a different refractive index to the first material; and
an electrode which is electrically contacted to only the defect part of the photonic crystal structure.

2 . The optical device of claim 1 , further comprising:
a layer of electrically insulating material overlying and in contact with the photonic crystal structure; a region of a third material in the layer of the electrically insulating material, which overlies and is in contact with only the defect part of the photonic crystal structure, wherein the third material is electrically conducting and wherein the electrode is electrically contacted to the defect part through the third material.

3 . The optical device of claim 2 , wherein the electrically insulating material is the same as the second material.

4 . The optical device of claim 1 , wherein the second material has a refractive index of less than 1.6 and is suitable for use as an electron-beam resist.

5 . The optical device of claim 1 , wherein the second material is hydrogen silsesquioxane.

6 . The optical device of claim 1 , wherein the photonic crystal structure is overlying and in contact with a material having a lower refractive index than the first material.

7 . The optical device of claim 1 , wherein the photonic crystal structure is overlying and in contact with a layer comprising a material which is the same as the second material.

8 . The optical device of claim 2 , wherein the electrode is a p-type electrode and further comprising:
an n-type electrode that is electrically contacted to the opposite surface of the photonic crystal structure to the p-type electrode, forming a p-n junction in a direction substantially perpendicular to the plane of the layers.

9 . The optical device of claim 1 , wherein the first material is a semiconducting material.

10 . The optical device of claim 1 , wherein the first material is GaAs and wherein the layer of the first material comprises a layer of low density InAs quantum dots.

11 . The optical device of claim 2 , wherein the third material is indium tin oxide.

12 . The optical device of claim 1 , wherein the defect part is a waveguide region along a direction substantially parallel to the plane of the layer.

13 . The optical device of claim 1 , wherein the defect part is a cavity region,

14 . The optical device of claim 13 , further comprising:
a waveguide region which is a second defect part of the lattice formed by a plurality of regions of the second material missing from the lattice; and wherein the waveguide region is optically coupled to the cavity region.

15 . The optical device of claim, further comprising:
an interferometer which is a plurality of defect parts of the lattice formed by a plurality of regions of the second material missing from the lattice; and wherein the interferometer is optically coupled to the defect part in which the quantum emitter is located.

16 . A method of fabricating an optical device, comprising the steps of:
forming a sacrificial layer on a substrate; forming a first electrical contact layer overlying and in contact with the sacrificial layer; forming a layer of a first material overlying and in contact with the electrical contact layer, the layer of the first material comprising a quantum emitter; removing a plurality of regions of the layer of the first material, the regions arranged in a regular lattice having at least one region missing from the lattice so that a defect is formed, to form a photonic crystal structure, wherein the quantum emitter is located in the defect part of the photonic crystal structure; removing a portion of the sacrificial layer; applying a second material such that it forms a layer overlying and in contact with the photonic crystal structure, wherein the second material is electrically insulating; removing a region of the layer of the second material, the region overlying the defect part of the photonic crystal structure; applying a layer of a third material in the region, wherein the third material is electrically conducting; electrically contacting an electrode to the third material.

17 . The method according to claim 16 , wherein the step of removing a plurality of regions of the layer of a first material comprises the steps of:
forming a resist on the layer of a first material; transferring a design mask to the resist using lithography; etching through the design mask down to the sacrificial layer.

18 . The method according to claim 16 , wherein the step of applying a layer of a second material comprises:
spin-coating the photonic crystal structure with the second material in a flowable state, such that it fills the space formed by removing a portion of the sacrificial layer and the plurality of regions and forms a layer overlying and in contact with the photonic crystal structure; and thermally treating the device such that the second material hardens.

19 . The method according to claim 16 , wherein the step of removing a region of the layer of the second material comprises:
transferring a design mask to the second material using lithography, wherein the second material acts as a resist; developing the design mask.

20 . The method according to claim 16 , wherein the first material is a semiconducting material, the second material is hydrogen silsesquioxane and the third material is indium tin oxide.

Assignees

• Toshiba Kk

Inventors

• Kalliakos Sokratis
• Skiba-Szymanska Joanna Krystyna
• Ellis David Julian Peter
• Shields Andrew James

Classifications

• G06N99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• H10H20/872

  Periodic patterns for optical field-shaping, e.g. photonic bandgap structures · CPC title

• H10H20/833

  Transparent materials · CPC title

• H10H20/824

  comprising only Group III-V materials, e.g. GaP · CPC title

• H10H20/0363

  of optical field-shaping means · CPC title