Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Purdue engineers lay groundwork for 'vertically oriented nanoelectronics'

03.08.2006
Engineers at Purdue University have developed a technique to grow individual carbon nanotubes vertically on top of a silicon wafer, a step toward making advanced electronics, wireless devices and sensors using nanotubes by stacking circuits and components in layers.

The technique might help develop a method for creating "vertically oriented" nanoelectronic devices, the electronic equivalent of a skyscraper, said Timothy S. Fisher, an associate professor of mechanical engineering who is leading the work with Timothy D. Sands, the Basil S. Turner Professor of Engineering.

"Verticality gives you the ability to fit more things into the same area, so you can add more and more layers while keeping the footprint the same size or smaller," Fisher said. "But before we can even think about using nanotubes in electronics, we have to learn how to put them where we want them."

The engineers first created a "thin film" containing two layers of aluminum sandwiching one ultra-thin layer of iron using electron-beam evaporation, a standard process employed in the semiconductor industry. The engineers then used "anodization," a process that causes metals to oxidize — like rusting — to selectively create tiny cylindrical cavities and turn the film into a "porous anodic alumina template" less than 1/100th the width of a human hair in thickness. During the process, an electric field was used to form a precisely aligned array of nanoscopic holes, turning aluminum into porous alumina, the oxidized form of aluminum also known as aluminum oxide.

A mixture of hydrogen and methane gas was then flowed into the template's holes, and microwave energy was applied to break down the methane, which contains carbon. The iron layer acted as a catalyst that prompted the carbon nanotubes to assemble from carbon originating in the methane, and the tubes then grew vertically out of the cavities.

"You get a single nanotube in each pore, and that's important because we can start to think about controlling how and where to put nanotubes to vertically integrate them for future electronic devices and sensing technologies," Sands said.

Findings are detailed in a research paper that appeared July 11 in the journal Nanotechnology. The paper was written by graduate students Matthew R. Maschmann and Aaron D. Franklin; postdoctoral research associate Placidus Amama; Dmitri Zakharov, a staff scientist at Purdue's Birck Nanotechnology Center; Eric Stach, an associate professor of materials engineering; Sands and Fisher.

"The pores in the template and the nanotubes that grow in the pores really self-assemble once you set the process in motion," said Stach, who used two types of electron microscopes to take images of the nanotubes emerging vertically from the cavities. The research is based at the Birck Nanotechnology Center in Purdue's Discovery Park, the university's hub for interdisciplinary research.

The cavities form within seconds, and the nanotubes take several minutes to finish growing. The holes vary in width from 30-50 nanometers. A nanometer, or billionth of a meter, is about as long as 10 atoms strung together.

Carbon nanotubes, which were discovered in the early 1990s, might enable industry to create new types of transistors and more powerful, energy-efficient computers, as well as ultra-thin "nanowires" for electronic circuits. Reaching that potential promise, however, won't be possible unless carbon nanotubes can be integrated with other parts of circuitry and devices, Sands said.

The experiments at Purdue yielded both single- and double-walled nanotubes, meaning they are made of either one or two single sheets of carbon atoms, yielding tubes about one nanometer in diameter.

Researchers will continue the work in efforts to understand which conditions are needed to produce single-wall tubes versus the double-wall variety and to learn how to produce more of one or the other.

Other researchers previously have made the templates, but the Purdue researchers are the first to add a layer of iron, which was Maschmann's idea, Fisher said.

"He was told by many people, including me, that it probably wouldn't work," Fisher said. "We were surprised to see that the nanotubes grow from the sidewall of the hole and then extend vertically."

Early applications are most likely in wireless computer networks and radar technology. Long-term uses are possible in new types of transistors, other electronic devices and circuits.

The research is funded by NASA, through the Purdue-based Institute for Nanoelectronics and Computing.

Timothy Fisher | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Power and Electrical Engineering:

nachricht Failures in power grids: Dynamically induced cascades
25.05.2018 | Technische Universität Dresden

nachricht Beyond the limits of conventional electronics: stable organic molecular nanowires
24.05.2018 | Tokyo Institute of Technology

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>