First controllable 2D nanopatterns imaged by Sandia researchers -- Nanotemplates for nanostructures

September 04, 2001

ALBUQUERQUE, N.M. -- Coffee beans spilled upon a table form no pattern, they're a mess, their distribution dictated by the laws of chance. The same was generally believed true of atoms deposited upon a substrate. Now, the first vision of a peaceable kingdom in which deposited atoms form orderly, controllable 2-D nanopatterns has been observed by researchers at the Department of Energy's Sandia National Laboratories.

Pattern control at this level means that nanotemplates could be formed to fine-tune the device characteristics of self-assembling nanostructures. Possibly, characteristics could be tailored for devices like photonic lattices, an advanced method for controlling light and of wide interest to the huge telecommunications industry.

The work, described in the Aug. 30 Nature, produced real-time video of atoms self-arranging themselves in the manner long predicted by a variety of theorists but contrary to ordinary intuition. Thus, such theories generally had been treated with a great deal of skepticism, says Sandia physicist Norm Bartelt: "There was no obvious route for atoms to arrange themselves in predicted patterns."

Says Sandia researcher Richard Plass, "Kinetics say that 10,000 moving atoms should go anywhere. Nobody really expected an assembly would arise."

Observation of the real-time assembly process, along with control over physical factors that influence that process, offer a means of finding out far more about the conditions under which atoms self-assemble than any theory could predict, and thus, how to influence that assembly into more desirable structures.

"There are many control knobs we can turn to create new patterns," says Bartelt. Among them are temperature and material composition.

The researchers observed atoms of lead deposited on a copper substrate forming, first, lead dots, then lead stripes, and then reverse dots -- copper becoming the dot material -- as more lead is added.

"The work -- which to our knowledge is the first unambiguous observation of the expected sequence of domain patterns -- helps understand the new physics that manifests itself at these small length scales," says Sandia project lead Gary Kellogg. "New materials with highly specialized properties necessary to meet defense and consumer needs can be fabricated only by tailoring the structure of the material on the nanometer scale. This work provides insight into how nature does this, and how humans can do the same."

Sandia researchers were able to record real-time, real-space images using a low-energy electron microscope (LEEM) that show exactly how the nanostructures are generated, self-assemble, and transform. "The close agreement between experiment and theory allows us to probe the key inter-atomic force parameters involved in the process," says Kellogg.

Theorists long have believed that competing attractive and repulsive inter-atomic interactions can lead to the spontaneous formation of ordered patterns in widely varying chemical and physical systems. Potentially, such patterns could be used as templates for nanostructure fabrications.

"There are precedents for people using these patterns for further growth of quantum dots," says Bartelt. "They can be the starting point of controllable patterns that extend into three dimensions."

Though models have clearly predicted the possibility of controlling any pattern's geometry and order, depending on temperature and amount of secondary metal introduced, experimental verification of these models had remained elusive till now.


Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia Media Relations Contact: Neal Singer, 505-845-7078,
Sandia Technical Contact: Norm Bartelt, 925-294-3061,

DOE/Sandia National Laboratories

Related Nanostructures Articles from Brightsurf:

Unlocking PNA's superpowers for self-assembling nanostructures
Researchers at Carnegie Mellon University have developed a method for self-assembling nanostructures with gamma-modified peptide nucleic acid, a synthetic mimic of DNA.

Machine learning enhances light-matter interactions in dielectric nanostructures
The discovery has promising possibilities for the development of a wide range of photonic devices and applications including those involved in optical sensing, optoacoustic vibrations, and narrowband filtering.

Electron correlations in carbon nanostructures
Graphene nanoribbons are only a few carbon atoms wide and have different electrical properties depending on their shape and width.

Paving a way to achieve unexplored semiconductor nanostructures
A research team of Ehime University paved a way to achieve unexplored III-V semiconductor nanostructures.

Nanostructures help to reduce the adhesion of bacteria
Scientists has shown how bacteria adhere to rough surfaces at the microscopic level.

Diamonds are forever: New foundation for nanostructures
Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) have fabricated a novel glass and synthetic diamond foundation that can be used to create miniscule micro -- and nanostructures.

How do atoms vibrate in graphene nanostructures?
Researchers from the University of Vienna, the Advanced Institute of Science and Technology in Japan, the company JEOL and La Sapienza University in Rome have developed a method capable to measure all phonons existing in a nanostructured material.

Heterophase nanostructures contributing to efficient catalysis
In the research on phase engineering of noble metal nanomaterials, amorphous/crystalline heterophase nanostructures have exhibited some intriguing properties.

Dresden physicists use nanostructures to free photons for highly efficient white OLEDs
Thanks to intensive research in the past three decades, organic light-emitting diodes (OLEDs) have been steadily conquering the electronics market -- from OLED mobile phone displays to roll-out television screens, the list of applications is long.

Self-healing DNA nanostructures
DNA assembled into nanostructures such as tubes and origami-inspired shapes could someday find applications ranging from DNA computers to nanomedicine.

Read More: Nanostructures News and Nanostructures Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to