Public Release: 

WSU physicists turn a crystal into an electrical circuit

Transparent, 3-D electronics can be configured and erased like an Etch A Sketch

Washington State University


IMAGE: Washington State University researchers used light to write a highly conducting electric path in a crystal. This opens up the possibility of transparent, three-dimensional electronics that, like an Etch-A-Sketch, can... view more 

Credit: Washington State University




"It opens up a new type of electronics where you can define a circuit optically and then erase it and define a new one," said McCluskey. "It's exciting that it's reconfigurable. It's also transparent. There are certain applications where it would be neat to have a circuit that is on a window or something like that, where it actually is invisible electronics."

Ordinarily, a crystal does not conduct electricity. But when the crystal strontium titanate is heated under the right conductions, it is altered so light will make it conductive. The phenomenon, called "persistent photoconductivity," also occurs at room temperature, an improvement over materials that require cooling with liquid nitrogen.

"We're still trying to figure out exactly what happens," said McCluskey. He surmises that heat forces strontium atoms to leave the material, creating light-sensitive defects responsible for the persistent photoconductivity.


"We look at samples that we exposed to light a year ago and they're still conducting," said McCluskey. "It may not retain 100 percent of its conductivity, but it's pretty big."


"It's an Etch A Sketch," said McCluskey. "We've done it a few cycles. Another engineering challenge would be to do that thousands of times."



