By adding combinations of carbon, hydrogen and oxygen atoms to stubborn, hard-to-evaporate metals like tungsten and platinum, researchers at the University of Minnesota were able to transform these metals into thin films in a cheaper and safer way. Image: Bharat Jalan MBE Lab, University of Minnesota.
By adding combinations of carbon, hydrogen and oxygen atoms to stubborn, hard-to-evaporate metals like tungsten and platinum, researchers at the University of Minnesota were able to transform these metals into thin films in a cheaper and safer way. Image: Bharat Jalan MBE Lab, University of Minnesota.

Researchers at the University of Minnesota have invented a cheaper, safer and simpler technology for transforming a 'stubborn' group of metals and metal oxides into the thin films used in electronics, computer components and other applications. The researchers report their advance in a paper in the Proceedings of the National Academy of Sciences.

They have also worked with the University of Minnesota’s Technology Commercialization Office to patent the technology, which has already garnered interest from industry.

Many metals and their compounds must be made into thin films before they can be used in technological products like electronics, displays, fuel cells and catalytic systems. But 'stubborn' metals – which include elements like platinum, iridium, ruthenium and tungsten, among others – are very difficult to convert into thin films because they require extremely high temperatures (usually more than 2000°C) to evaporate.

Typically, scientists synthesize these metal films using techniques like sputtering and electron beam evaporation. This latter technique involves melting and evaporating metals at high temperatures and allowing a film to form on top of wafers, and is very expensive, uses a lot of energy and may also be unsafe due to the high voltage used.

Now, researchers at the University of Minnesota have developed a way to evaporate stubborn metals at significantly lower temperatures – below 200°C instead of several thousand. By designing and adding organic ligands – combinations of carbon, hydrogen and oxygen atoms – to the metals, the researchers were able to substantially increase the materials’ vapor pressures, making them easier to evaporate at lower temperatures. Not only is their new technique simpler, but it also produces higher quality materials that are easily scalable.

"The ability to make new materials with ease and control is essential to transition into a new era of energy economy,” said Bharat Jalan, senior author of the paper, who is an expert in material synthesis and an associate professor in the University of Minnesota Department of Chemical Engineering and Materials Science (CEMS). "There is already a historical link between the innovation in synthesis science and the development of new technology. Millions of dollars go into making materials for various applications. Now, we’ve come up with a simpler and cheaper technology that enables better materials with atomic precision.”

Stubborn metals are used to make myriad products, from semiconductors for computer applications to display technology. Platinum, for example, makes a great catalyst for energy conversion and storage, and is being looked at for use in spintronic devices.

"Bringing down the cost and complexity of metal deposition while also allowing for deposition of more complex materials like oxides will play a large role in both industrial and research efforts," said William Nunn, a University of Minnesota chemical engineering and materials science graduate student and the paper’s first author. "Now that depositing these metals like platinum will become easier, we hope to see renewed interest in the more complex materials which contain these stubborn metals."

This story is adapted from material from the University of Minnesota, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.