Manufacturing Bits: Feb. 17

Swedish nano; CSI SEMs; birth of chemical bonds.

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Swedish nano
Sweden’s Lund University plans to build a pilot production facility for startups in the field of nanotechnology.

The facility would be used for Swedish companies and researchers to build products. This is for companies who do not have the funds to build their own facilities or buy expensive equipment. The project originates from the successful research into nanowires at Lund University. This, in turn, resulted in nanotechnology companies like Glo AB and Sol Voltaics AB.

Glo, for example, claims its technology sidesteps the technical limitations of current planar LED technology. The company’s nanowire light-emitting diodes (nLEDs) are based on a heterostructured semiconductor nanowire epitaxial growth technology. Each nanowire acts as an individual light-emitting diode (LED). “It allows for the creation of highly efficient, stable and ultimately unique red, green, blue (RGB) emitters out of one material system,” according to Glo.

SEM picture of actual nanowires from Glo (Source: Company)

SEM picture of actual nanowires from Glo (Source: Company)

The problem? Glo was forced to move from Sweden to Silicon Valley as a means to launch its production site, according to Lund University.

“With this new facility, we want to create the conditions to enable new companies to develop from the R&D phase to full production, without needing to leave Sweden,” says Lars Samuelson, a professor of nanophysics at Lund University, on the university’s web site.

CSI SEMs
Law enforcement agencies use serial numbers to track ownership of firearms in criminal cases, but the numbers can be easily removed. Agencies attempt to restore the numbers with acid, electrolytic etching or polishing, but these methods sometimes don’t work, according to National Institute of Standards and Technology (NIST).

Using tools from the semiconductor industry, NIST has made a possible breakthrough in forensic science. NIST has devised a technique called electron backscatter diffraction (EBSD). The technology has the ability to read imprints on steel that have been removed by polishing.

EBSD makes use of a traditional scanning electron microscope (SEM). The SEM scans a beam of electrons over the surface. Then, the electrons strike atoms in the target and bounce back. The electrons form patterns, which, in turn, reveal the crystal’s structure in the nanometer range. Software can then reveal crystal damage.

For an experiment to recover serial numbers that have been destroyed, NIST researchers hand-stamped X imprints into stainless steel (first image). Then they polished away the imprints (second image). Researchers recovered the imprints (third image) using a SEM-based technology. (Source: NIST)

For an experiment to recover serial numbers that have been destroyed, NIST researchers hand-stamped X imprints into stainless steel (first image). Then they polished away the imprints (second image). Researchers recovered the imprints (third image) using a SEM-based technology. (Source: NIST)

In one experiment, NIST hammered the letter “X” into a polished stainless steel plate. The letter stamps were as deep as 140 micrometers. The metal was polished to remove the letters. Using EBSD, NIST found evidence of metal deformation down to 760 micrometers below the surface, which was deeper than the actual “X” stamps.

Currently, this technology is in the experimental stage and remains too slow. It takes three days to reconstruct an 8-character number. In the future, NIST hopes to reduce the procedure down to about an hour.

Birth of chemical bonds
Using an X-ray laser, the Department of Energy’s SLAC National Accelerator Laboratory watched a chemical bond being born.

More specifically, researchers obtained the first glimpse of the transition state where two atoms begin to form a weak bond on the way to becoming a molecule. This could have an impact on the understanding of how chemical reactions take place. It will also allow researchers to design reactions that generate energy in new products.

This illustration shows atoms forming a tentative bond. (Source: SLAC)

This illustration shows atoms forming a tentative bond. (Source: SLAC)

The experiments took place at SLAC’s Linac Coherent Light Source (LCLS). The LCLS was used to study the same reaction that neutralizes carbon monoxide (CO) from car exhaust in a catalytic converter.

The reaction takes place on the surface of a catalyst. This, in turn, grabs CO and oxygen atoms and holds them next to each other. Then, they form carbon dioxide.

Researchers attached CO and oxygen atoms to the surface of a ruthenium catalyst. A pulse from an optical laser heated the catalyst to 2,000 kelvins. Researchers were able to observe this process with X-ray laser pulses. It detected changes in the arrangement of the atoms’ electrons, which occurred in femtoseconds, or quadrillionths of a second.

“This is the very core of all chemistry. It’s what we consider a Holy Grail, because it controls chemical reactivity,” said Anders Nilsson, a professor at the SLAC/Stanford SUNCAT Center for Interface Science and Catalysis and at Stockholm University who led the research, on SLAC’s web site. “But because so few molecules inhabit this transition state at any given moment, no one thought we’d ever be able to see it.”