title: Extreme electronic bandgap modification in laser-crystallized silicon optical fibres.
abstract: For decades now, silicon has been the workhorse of the microelectronics revolution and a key enabler of the information age. Owing to its excellent optical properties in the near- and mid-infrared, silicon is now promising to have a similar impact on photonics. The ability to incorporate both optical and electronic functionality in a single material offers the tantalizing prospect of amplifying, modulating and detecting light within a monolithic platform. However, a direct consequence of silicon's transparency is that it cannot be used to detect light at telecommunications wavelengths. Here, we report on a laser processing technique developed for our silicon fibre technology through which we can modify the electronic band structure of the semiconductor material as it is crystallized. The unique fibre geometry in which the silicon core is confined within a silica cladding allows large anisotropic stresses to be set into the crystalline material so that the size of the bandgap can be engineered. We demonstrate extreme bandgap reductions from 1.11 eV down to 0.59 eV, enabling optical detection out to 2,100 nm.
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Noel
authors.initials: N
authors.lastname: Healy
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Sakellaris
authors.initials: S
authors.lastname: Mailis
authors.affiliation: 1] Institute of Thermophysics, SB RAS, Novosibirsk 630090, Russia [2] HiLASE, Institute of Physics ASCR, 18221 Prague, Czech Republic.
authors.forename: Nadezhda M
authors.initials: NM
authors.lastname: Bulgakova
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Pier J A
authors.initials: PJ
authors.lastname: Sazio
authors.affiliation: Department of Chemistry and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Todd D
authors.initials: TD
authors.lastname: Day
authors.affiliation: Department of Chemistry and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Sparks
authors.affiliation: Department of Chemistry and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Hiu Y
authors.initials: HY
authors.lastname: Cheng
authors.affiliation: Department of Chemistry and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: John V
authors.initials: JV
authors.lastname: Badding
authors.affiliation: Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Peacock