NEXT project receives secretary’s achievement award

On Wednesday, Mar. 14, Under Secretary of Energy Mark Menezes presented the Secretary’s Achievement Award—a U.S. Department of Energy (DOE) Office of Project Management (PM) Award—to the National Synchrotron Light Source II (NSLS-II) Experimental Tools (NEXT) project management team for completing the project on schedule and under budget, and for delivering scientific instruments to NSLS-II that will benefit research for years to come.

The NEXT project team coordinated the development and construction of five new beamlines (experimental stations) at NSLS-II, a highly advanced synchrotron light source and a DOE Office of Science User Facility located at DOE’s Brookhaven National Laboratory. Scientists use NSLS-II’s ultra-bright light to study materials with nanoscale resolution and exquisite sensitivity. The five new beamlines developed through NEXT complement the existing beamline portfolio at NSLS-II, and offer new, unique, and cutting-edge scientific capabilities.

“These state-of-the-art beamlines support the DOE Office of Science mission to deliver scientific discoveries and major scientific tools to transform our understanding of nature and to advance the energy, economic, and national security of the United States,” said Robert Caradonna, DOE Brookhaven Site Office Federal Project Director. “This award reflects the drive and dedication of the NEXT project team that made this endeavor a huge success. It was an honor to work with such talented people on such an important a project.”

>Read more on the NSLS-II website

Image: The NEXT team celebrates the completion of the project in NSLS-II’s lobby.
Credit: NSLS II

Scientists have a new way to gauge the growth of nanowires

In a new study, researchers from the U.S. Department of Energy’s Argonne and Brookhaven National Laboratories observed the formation of two kinds of defects in individual nanowires, which are smaller in diameter than a human hair.

These nanowires, made of indium gallium arsenide, could be useful for a wide range of applications in a field scientists have termed optoelectronics, which encompasses devices that work by converting light energy into electrical impulses. Fiber optic relays are a good example.

The effectiveness of these devices, however, can be affected by tiny defects in their components. These defects, which can change both the optical and electronic properties of these materials, interest scientists who seek to tailor them to boost the functionality of future optoelectronics, including materials that will be able to manipulate quantum information.

>Read more on the NSLS-II website and the Advanced Photon Source website

Image: Argonne and Brookhaven researchers observed two kinds of defects forming in individual nanowires, depicted here. These nanowires are smaller in diameter than a human hair.
Credit: Megan Hill/Northwestern University

New technique simplifies creation of nanoparticle ‘magic-sized clusters’

One of the cool things about nanoparticles is also what makes them so difficult to work with: the fact that their properties are dependent on their size.

A critical challenge in translating nanomaterials from the laboratory into commercial applications, such as lighting or optical memory storage, is making a batch of nanoparticles all the same size. Two Cornell research groups have joined forces to lay out a solution for this issue.

Researchers in the labs of Richard Robinson and Tobias Hanrath – using X-ray analysis at the Cornell High Energy Synchrotron Source (CHESS) – have developed a new nanosynthetic pathway to achieve ultra-pure and highly stable groups of same-sized particles – known as “magic-sized clusters.”

Their paper, “Mesophase Formation Stabilizes High-Purity Magic-Sized Clusters,” published online Jan. 27 in the Journal of the American Chemical Society, and will be on a cover of the March 14 print edition. Lead authors are Curtis Williamson, doctoral student in both the Robinson and Hanrath groups, and Douglas Nevers, doctoral student in the Hanrath Group. Lena Kourkoutis, assistant professor of applied and engineering physics, also contributed.

>Read more on the Cornell Hight Energy Synchrotron Source (CHESS) website

Image: Schematic of the magic-sized clusters hexagonal mesophase. The mesophase (left) is an assembly of nanofibers (center), which are composed of magic-sized clusters (right).
Credit: Richard Robinson

Scientists observe nanowires as they grow

X-ray experiments reveal exact details of self-catalysed growth for the first time

At DESY’s X-ray source PETRA III, scientists have followed the growth of tiny wires of gallium arsenide live. Their observations reveal exact details of the growth process responsible for the evolving shape and crystal structure of the crystalline nanowires. The findings also provide new approaches to tailoring nanowires with desired properties for specific applications. The scientists, headed by Philipp Schroth of the University of Siegen and the Karlsruhe Institute of Technology (KIT), present their findings in the journal Nano Letters. The semiconductor gallium arsenide (GaAs) is widely used, for instance in infrared remote controls, the high-frequency components of mobile phones and for converting electrical signals into light for fibre optical transmission, as well as in solar panels for deployment in spacecraft.

To fabricate the wires, the scientists employed a procedure known as the self-catalysed Vapour-Liquid-Solid (VLS) method, in which tiny droplets of liquid gallium are first deposited on a silicon crystal at a temperature of around 600 degrees Celsius. Beams of gallium atoms and arsenic molecules are then directed at the wafer, where they are adsorpted and dissolve in the gallium droplets. After some time, the crystalline nanowires begin to form below the droplets, whereby the droplets are gradually pushed upwards. In this process, the gallium droplets act as catalysts for the longitudinal growth of the wires. “Although this process is already quite well established, it has not been possible until now to specifically control the crystal structure of the nanowires produced by it. To achieve this, we first need to understand the details of how the wires grow,” emphasises co-author Ludwig Feigl from KIT.

>Read more on the FLASH and PETRA III at DESY website

Image: A single nanowire, crowned by a gallium droplet, as seen with the scanning electron microscope (SEM) of the DESY NanoLab.
Credit: DESY, Thomas Keller

How can asbestos teach us about carbon nanotubes?

Carbon nanotubes (CNTs) are already used in industry.

They have a fibrous structure that resembles that of asbestos. A team from University ofTrieste, IRCCS Burlo Garofolo, University of Turin, Elettra (Italy) and ESRF has studied both materials at the ESRF’s beamline ID21 and Elettra and has found that the presence of iron impurities in CNTs causes an asbestos-like toxicity in pleural cells. The scientists publish their results in Scientific Reports today.

>Read more on the ESRF website

Image: An artistic impression of a carbon nanotube.
Credits: Model.la.

Bing-Joe Hwang received National Chair Professorship from Ministry of Education

Exceptional award for this NSRRC User

The Ministry of Education recently announced the recipients of the 21st National Chair Professorships and the 61st Academic Awards. Prof. Bing-Joe Hwang, a long-term user of NSRRC, was given the National Chair Professorship in the category of Engineering and Applied Sciences. Prof. Hwang is a Chair Professor in Chemical Engineering at National Taiwan University of Science and Technology. He is also an adjunct scientist of NSRRC. His research interests include electrochemistry, nanomaterials, nanoscience, fuel cells, lithium ion batteries, solar cells, sensors, and interfacial phenomena.