Photonic crystal could lead to improved solar cells and lasers

‘We’ve discovered a way to change the three-dimensional structure of a well-established semiconductor material to enable new optical properties while maintaining its very attractive electrical properties,’ said Paul Braun, a professor of materials science, engineering and chemistry, who led the research effort.

Photonic crystals are materials that can control or manipulate light thanks to their unique physical structures; they can induce unusual phenomena and affect photon behaviour in ways that traditional optical materials and devices can’t.

Previous attempts at making 3D photonic crystals are said to have resulted in devices that are only optically active; they can direct light but are not electronically active, so they can’t turn electricity to light or vice versa.

The Illinois team’s photonic crystal is claimed to have both properties.

‘With our approach to fabricating photonic crystals, there’s a lot of potential to optimise electronic and optical properties simultaneously,’ said Erik Nelson, a former graduate student in Braun’s lab who now is a postdoctoral researcher at Harvard University. ‘It gives you the opportunity to control light in ways that are very unique to control the way it’s emitted and absorbed or how it propagates.’