The 2007 NASA Tech Briefs National Nano Engineering Conference (NNEC), to be held November 14-15 at the Boston Marriott Copley Place, is produced for design engineers who want to know what’s real, what’s close, and what might be coming in the world of nanotechnology. The NNEC will help you keep pace with the engineering and technology innovations behind the latest nanotech breakthroughs. Included will be technical presentations and exhibits from companies leading the nanotech industry in application areas such as biomedical, electronics, advanced materials, energy and the environment, and business. You’ll also find networking opportunities, and the expert insight you’ll need to stay ahead of the small-tech curve.
The NNEC also features the presentation of the Nanotech Briefs® Nano 50™ Awards. This year’s third annual awards recognize the top 50 innovators, technologies, and products that have significantly impacted — or are expected to impact — the state of the art in nanotechnology. The Nano 50 will be presented at a special awards dinner held on Wednesday, November 14. For a complete list of 2007 winners, visit here.
A number of this year’s Nano 50 winners will present their award-winning technologies in panel sessions, including those featured here. Visit here for more information and to register for the NNEC.
Carbon Nanotubes Detect Chemical Vapors
The U.S. Naval Research Laboratory (NRL) is developing a chemical sensor technology based on single-walled carbon nanotubes (SWNTs). Dr. Eric Snow is head of the Electronic Materials Branch at the NRL, and is a 2007 Nano 50 winner in the Innovator category.
SWNTs possess many unique properties that make them well suited for the direct electronic detection of trace chemical vapors. These properties include the structure of SWNTs in which every atom is a surface atom. This infinite surface-to-volume ratio produces a high sensitivity to its local chemical environment. SWNTs also exhibit near-ballistic electron transport along the nanotube axis, which provides an efficient electrical conduit to transmit changes in electrical properties caused by the presence of a molecular adsorbate. Finally, the chemically inert graphitic structure of SWNTs provides reliable operation in harsh environments.
But in order to take advantage of these properties, there are a number of technical challenges that must be overcome before one can incorporate SWNTs into a commercial chemical detection system. These include the development of an inexpensive, high-yield fabrication procedure; reduction of 1/f noise; optimization of the electronic transduction mechanism; and providing chemical specificity. Dr. Snow’s presentation will describe the NRL’s approach to addressing each of these issues. He also will provide an update on the NRL’s progress toward developing a SWNT-based vapor detection system for trace levels of toxic industrial chemicals, chemical warfare agents, and explosives.
Learn more about the Naval Research Laboratory’s work in SWNT-based chemical detection sensors from Dr. Snow during the Nanodevice Fabrication Session at 2:00 pm on Wednesday, November 14.
Helium Ion Microscopy
Helium Ion Microscopy (HIM) is a new, potentially revolutionary imaging and particle beam measurement methodology. The first commercial HIM has been installed at the National Institute of Standards and Technology in Maryland. Dr. Michael T. Postek is the Chief of the Precision Engineering Division and Program Manager of the Nanomanufacturing Program in the Manufacturing Engineering Laboratory (MEL) at NIST, and is a 2007 Nano 50 winner in the Innovator category. A research program within MEL will study the imaging mechanisms, modeling, analytical capabilities, and uncertainties regarding dimensional measurements made with this microscope.
This methodology presents an potentially revolutionary approach to measurements that has several potential advantages over the traditional scanning electron microscope (SEM) currently in use in research and manufacturing facilities across the world. The HIM is unique but also complimentary to the traditional SEM. Due to the very high source brightness, and the shorter wavelength of the helium ions, it is theoretically possible to focus the helium ion beam into a smaller probe size relative to that of an electron beam of an SEM, so higher resolution is possible. In an SEM, an electron beam interacts with the sample and a variety of signals is generated, collected, and imaged. This interaction zone may be quite large, depending upon the electron energy and sample material. Conversely, when the helium ion beam interacts with the sample, it does not have as large an excitation volume and thus, the image collected contains more surface-related information and can potentially provide atomic resolution images on a wide range of materials.
The current suite of HIM detectors can provide information on topographic, material, crystallographic, and electrical properties of the sample. Compared to an SEM, the secondary electron yield is quite high, allowing for imaging at extremely low beam currents. The relatively low mass of the helium ion, in contrast to other ion sources such as gallium, results in no discernable damage to the sample.
Learn more about NIST’s Helium Ion Microscope from Dr. Postek in the Advances in Imaging/Microscopy Session at 11:00 am on Thursday, November 15.
Novel Method for Creating Carbon Nanotubes
Dr. Jeanette Benavides, a researcher at NASA’s Goddard Space Flight Center in Maryland, has developed a simpler, safer, and much less costly process to make single-walled carbon nanotubes (SWCNTs) without a metal catalyst. For her discovery, Dr. Benavides is a Nano 50 winner in the Technology category.
Nanotubes can be either semiconductors or conductors, depending on how they are made. The key to Dr. Benavides’ process was understanding how to produce bundles of nanotubes without using metal, which reduced the costs tremendously and made a better-quality product.
The improved production process could increase the prevalence of carbon nanotube technology in many areas, including medical applications such as portable/field equipment, implantable biosensors, artificial limbs and organs, and drug delivery; miniature and consumer electronics; research instruments (e.g., microscopy); fuel cells; radiation shielding; and innovative polymers for a wide range of applications.
Earlier this year, NASA Goddard licensed the patented technique for manufacturing the SWCNTs to Idaho Space Materials (ISM) in Boise. Now the carbon nanotubes based on this creation process are being used by researchers and companies working on new materials with ceramics and polymers.
The steps toward the discovery of this process will be discussed along with a description of the process and properties of the single-walled carbon nanotubes produced. These properties include solubility in acetone and alcohol and assembly into three-dimensional structures. Potential applications will also be discussed.
Learn more about Dr. Benavides’ process for making SWCNTs in the Nanomaterial Fabrication/Manufacturing Session at 11:15 am on Wednesday, November 14.