Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Advance brings 'hyperbolic metamaterials' closer to reality

"Hyperbolic metamaterials" could bring optical advances including powerful microscopes, quantum computers and high-performance solar cells. The graphic at left depicts a metamaterial's "hyperbolic dispersion" of light. At center is a high-resolution transmission electron microscope image showing the interface of titanium nitride and aluminum scandium nitride in a "superlattice" that is promising for potential applications. At right are two images created using a method called fast Fourier transform to see individual layers in the material. Purdue University image
"Hyperbolic metamaterials" could bring optical advances including powerful microscopes, quantum computers and high-performance solar cells. The graphic at left depicts a metamaterial's "hyperbolic dispersion" of light. At center is a high-resolution transmission electron microscope image showing the interface of titanium nitride and aluminum scandium nitride in a "superlattice" that is promising for potential applications. At right are two images created using a method called fast Fourier transform to see individual layers in the material.

Purdue University image

Abstract:
Epitaxial superlattices with titanium nitride as a plasmonic component for optical hyperbolic metamaterials

Gururaj V. Naik,1 Bivas Saha,2 Jing Liu,3 Sammy M. Saber,2 Eric Stach,2 Joseph MK Irudayaraj,3 Timothy D. Sands,1,2 Vladimir M. Shalaev1 and Alexandra Boltasseva*,1,4

1 School of Electrical and Computer Engineering, and Birck Nanotechnology Center, Purdue

University

2 School of Materials Engineering, and Birck Nanotechnology Center, Purdue University

3 Department of Agricultural and Biological Engineering, and Bindley Bioscience Center,

Purdue University

4 DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark CORRESPONDING AUTHOR: *Alexandra Boltasseva

Titanium nitride (TiN) is a plasmonic material having optical properties resembling gold. Unlike gold however, TiN is CMOS-compatible, mechanically strong, and thermally stable at higher temperatures. Additionally, TiN can be grown in smooth, ultra-thin crystalline films, which are useful in constructing many plasmonic and metamaterial devices including hyperbolic metamaterials (HMMs). Hyperbolic metamaterials have been shown to exhibit exotic optical properties, including extremely high broadband photonic densities of states (PDOS), which are useful in quantum plasmonics applications. However, the extent to which the exotic properties of HMMs can be realized has been seriously limited by fabrication constraints and material properties. Here, we address these issues by realizing an epitaxial superlattice as an HMM. The superlattice consists of ultra-smooth layers as thin as 5 nm and exhibits sharp interfaces, which are essential for high-quality HMM devices. Our study reveals that such a TiN-based superlattice HMM provides a higher PDOS enhancement than gold- or silver-based HMMs. Given the advantages of TiN as a CMOS compatible plasmonic material, this demonstration brings a paradigm shift to the field of metamaterials similar to the way heterostructures did to the field of solid-state light sources.

Advance brings 'hyperbolic metamaterials' closer to reality

West Lafayette, IN | Posted on May 15th, 2014

Researchers have taken a step toward practical applications for "hyperbolic metamaterials," ultra-thin crystalline films that could bring optical advances including powerful microscopes, quantum computers and high-performance solar cells.

New developments are reminiscent of advances that ushered in silicon chip technology, said Alexandra Boltasseva, a Purdue University associate professor of electrical and computer engineering.

Optical metamaterials harness clouds of electrons called surface plasmons to manipulate and control light. However, some of the plasmonic components under development rely on the use of metals such as gold and silver, which are incompatible with the complementary metal-oxide-semiconductor (CMOS) manufacturing process used to construct integrated circuits and do not transmit light efficiently.

Now researchers have shown how to create "superlattice" crystals from layers of the metal titanium nitride and aluminum scandium nitride, a dielectric, or insulator. Superlattices are crystals that can be grown continuously by adding new layers, a requirement for practical application.

"This work is a very important step in terms of fundamental contributions in materials science and optics as well as paving the way to some interesting applications," Boltasseva said. "We believe this demonstration brings a paradigm shift to the field of metamaterials similar to developments that led to dramatic advances in silicon technology."

Research findings are detailed in a paper appearing this week in the online Early Edition of Proceedings of the National Academy of Sciences.

Researchers created the superlattices using a method called epitaxy, "growing" the layers inside a vacuum chamber with a technique known as magnetron sputtering. It is difficult to use the technique to create structures that have sharply defined, ultra-thin and ultra-smooth layers of two different materials.

"This is one of the first reports of a metal-dielectric epitaxial superlattice," said Purdue doctoral student Bivas Saha, co-lead author of the PNAS paper with Gururaj V. Naik, a former Purdue doctoral student and now a postdoctoral scholar at Stanford University.

The list of possible applications for metamaterials includes a "planar hyperlens" that could make optical microscopes 10 times more powerful and able to see objects as small as DNA, advanced sensors, more efficient solar collectors, and quantum computing.

"Plasmonic and metamaterial devices require good material building blocks, both plasmonic and dielectric, in order to be useful in any real-world application," Boltasseva said. "Here, we develop both plasmonic and dielectric materials that can be grown epitaxially into ultra-thin and ultra-smooth layers with sharp interfaces."

Metamaterials have engineered surfaces that contain features, patterns or elements, such as tiny antennas or alternating layers of nitrides that enable unprecedented control of light. Under development for about 15 years, the metamaterials owe their unusual potential to precision design on the scale of nanometers.

The PNAS paper was authored by Naik; Saha; doctoral students Jing Liu and Sammy M. Saber; Eric Stach, a researcher at Brookhaven National Laboratory; Joseph Irudayaraj, a professor in Purdue's Department of Agricultural and Biological Engineering; Timothy D. Sands, executive vice president for academic affairs and provost and Basil S. Turner Professor of Engineering in the Schools of Materials Engineering and Electrical and Computer Engineering; Vladimir M. Shalaev, scientific director of nanophotonics at Purdue's Birck Nanotechnology Center and a distinguished professor of electrical and computer engineering; and Boltasseva.

"This work results from a unique collaboration between nanophotonics and materials science," Boltasseva said.

The hyperbolic metamaterial behaves as a metal when light is passing through it in one direction and like a dielectric in the perpendicular direction. This "extreme anisotropy" leads to "hyperbolic dispersion" of light and the ability to extract many more photons from devices than otherwise possible, resulting in high performance.

The layers of titanium nitride and aluminum scandium nitride used in this study are each about 5 to 20 nanometers thick. However, researchers have demonstrated that such superlattices can also be developed where the layers could be as thin as 2 nanometers, a tiny dimension only about eight atoms thick.

"People have tried for more than 50 years to combine metals and semiconductors with atomic-scale precision to build superlattices," Saha said. "However, this is one of the first demonstrations of achieving that step. The fascinating optical properties we see here are a manifestation of extraordinary structural control that we have achieved."

The feat is possible by choosing a metal and dielectric with compatible crystal structures, enabling the layers to grow together as a superlattice. The researchers alloyed aluminum nitride with scandium nitride, meaning the aluminum nitride is impregnated with scandium atoms to alter the material's crystal lattice to match titanium nitride's.

"The possibility of growing both metal and dielectric material components as a whole epitaxial system is indispensable for realizing high-performance metamaterials," Saha said. "One of the stumbling blocks is the fact that common dielectrics such as silica, alumina and other oxides cannot be used in combination with metallic components such as metal nitrides because the deposition processes are not compatible with each other."

Both of the materials should possess the same or compatible crystal structures.

"In general, a lattice mismatch of less than 5 percent is necessary for growing epitaxial quality films," he said.

A U.S. patent application has been filed through the Purdue Office of Technology Commercialization.

The material has been shown to work in a broad spectrum from near-infrared to visible light, potentially promising a wide array of applications.

"That's a novel part of this work - that we can create a superlattice metamaterial showing hyperbolic dispersion in the visible spectrum range," Boltasseva said.

The near-infrared is essential for telecommunications and optical communications, and visible light is important for sensors, microscopes and efficient solid-state light sources.

"Most interesting is the realm of quantum information technology," she said.

Computers based on quantum physics would have quantum bits, or "qubits," that exist in both the on and off states simultaneously, dramatically increasing the computer's power and memory. Quantum computers would take advantage of a phenomenon described by quantum theory called "entanglement." Instead of only the states of one and zero used in conventional computer processing, there are many possible "entangled quantum states" in between one and zero, increasing the capacity to process information.

The research has been funded in part by the U.S. Army Research Office and the National Science Foundation.

####

For more information, please click here

Contacts:
Writer:
Emil Venere

765-494-4709

Sources:
Alexandra Boltasseva
765-494-0301


Bivas Saha

Copyright © Purdue University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Nanoparticles Increase Durability of Concrete Decorations in Cold Areas January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Imaging

Graphene brings quantum effects to electronic circuits January 22nd, 2015

EnvisioNano: An image contest hosted by the National Nanotechnology Initiative (NNI) January 22nd, 2015

Oxford Instruments Asylum Research Releases New Application Note: “AFM Applications in Polymer Science and Engineering” January 21st, 2015

One nanoparticle, 6 types of medical imaging: Tomorrow's doctors could use this technology to obtain a super-clear picture of patients' organs and tissues January 20th, 2015

Thin films

New Molecular Beam Epitaxy deposition equipment at the ICN2 January 22nd, 2015

Self-assembled nanotextures create antireflective surface on silicon solar cells: Nanostructured surface textures-with shapes inspired by the structure of moths' eyes-prevent the reflection of light off silicon, improving conversion of sunlight to electricity January 21st, 2015

Govt.-Legislation/Regulation/Funding/Policy

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Harper Government Supports Research Innovation in Western Canada January 22nd, 2015

EnvisioNano: An image contest hosted by the National Nanotechnology Initiative (NNI) January 22nd, 2015

Quantum Computing

Graphene brings quantum effects to electronic circuits January 22nd, 2015

Improved interface for a quantum internet January 16th, 2015

Rice-sized laser, powered one electron at a time, bodes well for quantum computing January 15th, 2015

Toward quantum chips: Packing single-photon detectors on an optical chip is a crucial step toward quantum-computational circuits January 9th, 2015

Discoveries

Nanoparticles Increase Durability of Concrete Decorations in Cold Areas January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Materials/Metamaterials

Engineering self-assembling amyloid fibers January 26th, 2015

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Silver nanowires demonstrate unexpected self-healing mechanism: The material has potential for flexible electronics January 23rd, 2015

Announcements

Nanoparticles Increase Durability of Concrete Decorations in Cold Areas January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Nanoparticles Increase Durability of Concrete Decorations in Cold Areas January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Tools

Graphene brings quantum effects to electronic circuits January 22nd, 2015

EnvisioNano: An image contest hosted by the National Nanotechnology Initiative (NNI) January 22nd, 2015

New Molecular Beam Epitaxy deposition equipment at the ICN2 January 22nd, 2015

New method to generate arbitrary optical pulses January 21st, 2015

Patents/IP/Tech Transfer/Licensing

Carbon nanotube finding could lead to flexible electronics with longer battery life January 14th, 2015

Liquipel Receives US Patent on Environmentally Friendly, Watersafe Treatment of Electronics: U.S. Patent Office Finds Watersafe™ Treatment Covers Cell Phones, Smart Phones, Tablets, Computers and More January 5th, 2015

New non-invasive method can detect Alzheimer's disease early: MRI probe technology shows brain toxins in living animals for first time December 22nd, 2014

Silicon Valley-Based Foresight Valuation Launches STR-IP™, a New Initiative for Startups to Discover the Value of Their Intellectual Property December 18th, 2014

Military

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Laser-generated surface structures create extremely water-repellent metals: Super-hydrophobic properties could lead to applications in solar panels, sanitation and as rust-free metals January 20th, 2015

Energy

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

New technique helps probe performance of organic solar cell materials January 23rd, 2015

Transparent artificial nacre: A brick wall at the nanoscale January 22nd, 2015

Photonics/Optics/Lasers

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

New method to generate arbitrary optical pulses January 21st, 2015

New signal amplification process set to transform communications, imaging, computing: UC San Diego researchers discover a mechanism to amplify signals in optoelectronic systems that is far more efficient than standard processes January 21st, 2015

Solar/Photovoltaic

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

New technique helps probe performance of organic solar cell materials January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

Quantum nanoscience

Graphene brings quantum effects to electronic circuits January 22nd, 2015

Nano-beaker offers insight into the condensation of atoms January 21st, 2015

Atoms can be in 2 places at the same time: Researchers of the University of Bonn have shown that cesium atoms do not follow well-defined paths January 20th, 2015

Two or one splashing? It's different! Physicist at the University of Bonn observe light-matter interaction with two atoms for the first time January 16th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE