Extreme Band-Gap Reduction in Laser-crystallized Si Fibers

Amorphous silicon wires embedded in silica templates by high-pressure chemical vapor deposition (a technique also used to create ordered 3D metalattices) can be crystallized by a laser. Modeling reveals that shrinkage of the amorphous silicon upon crystallization creates extreme strain in these wires. A combination of experiment and theory suggests that the band gap can change by nearly a factor of two due to this strain. It may thus be possible to employ the technologically versatile silicon platform for detectors at near -IR to mid-IR wavelengths.