Published in the journal ADVANCED MATERIALS
"We have developed a new, high-pressure, plasma-free approach to creating large-area, thin-film semiconductors," said John Badding, professor of chemistry, physics, and materials science and engineering at Penn State and the leader of the research team. "By putting the process under high pressure, our new technique could make it less expensive and easier to create the large, flexible semiconductors that are used in flat-panel monitors and solar cells and are the second most commercially important semiconductors."
Thin-film silicon semiconductors typically are made by the process of chemical vapor deposition, in which silane -- a gas composed of silicon and hydrogen -- undergoes a chemical reaction to deposit the silicon and hydrogen atoms in a thin layer to coat a surface. To create a functioning semiconductor, the chemical reaction that deposits the silicon onto the surface must happen at a low enough temperature so that the hydrogen atoms are incorporated into the coating rather than being driven off like steam from boiling water. With current technology, this low temperature is achieved by creating plasma -- a state of matter similar to a gas made up of ions and free electrons -- in a large volume of gas at low pressure. Massive and expensive reactors so large that they are difficult to ship by air are needed to generate the plasma and to accommodate the large volume of gas required.