Breakthrough technique offers prospect of silicon detectors for telecommunications

For decades, silicon has been the foundation of the microelectronics revolution and, owing to its excellent optical properties in the near- and mid-infrared range, is now promising to have a similar impact on photonics.

The team's research, reported in the journal Nature Materials, describes engineering the electronic band structure of laser-crystallised silicon photonic devices to help overcome one of the key challenges of using silicon in data communications.

The laser processing technique has been developed for their silicon optical fibre platform. It demonstrates that it is possible to completely crystallise the core material, while at the same time writing in large stresses to modify the optoelectronic properties, achieving extreme bandgap reductions from 1.11 eV down to 0.59 eV, enabling optical detection out to 2,100 nm.

Incorporating silicon materials within the fibre geometry avoids the issues associated with coupling between the micron-sized fibres used for the transport of light, and the nanoscale waveguides on-chip that are employed for data processing and communications systems.

Dr Anna Peacock, an Associate Professor in Optoelectronics who heads the group in the ORC, comments: “The ability to grow single crystal-like materials directly inside the fibre core is a truly exciting prospect as, for the first time, the optoelectronic properties of the silicon fibre devices will be able to approach those of their on-chip counterparts.”

Dr Noel Healy, the lead researcher on the project, adds: “Our discovery uses large variable strains to provide unprecedented control over silicon's optoelectronic properties. This greatly increases the number of potential applications for the material in both electrical and optical applications.

“Our paper shows that we can halve the material's bandgap energy. That means silicon can now be considered as a medium for optical detection all the way through the telecommunications band.”

Fellow researcher Dr Sakellaris Mailis points out that this versatile laser processing method can be easily extended to a wide range of material systems.

Full bibliographic information

Extreme electronic bandgap modification in laser-crystallized ​silicon optical fibres
Noel Healy, Sakellaris Mailis, Nadezhda M. Bulgakova, Pier J. A. Sazio, Todd D. Day, Justin R. Sparks, Hiu Y. Cheng, John V. Badding & Anna C. Peacock
Nature Materials (2014)
doi:10.1038/nmat4098
To read the paper in full visit: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4098.html

Notes for editors

1. The attached image shows a single-crystal-like silicon core fibre with a thermodynamic snap shot of the laser heating.

2. Nature Materials i s a respected multi-disciplinary journal that brings together cutting-edge research across the entire spectrum of materials science and engineering.

To read the paper in full visit: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4098.html

3. The full collaborative research team includes Professor N. Bulgakova currently at HiLASE, Institute of Physics ASCR; Professor J. Badding, Dr T. Day, Dr J. Sparks, and Ms H. Cheng of the Department of Chemistry and the Materials Research Institute at Penn State University, and Dr P. Sazio of the ORC. A significant component of the work was conducted using the Diamond Light Source with the assistance of Dr K. Ignatyev.

4. Through world-leading research and enterprise activities, the University of Southampton connects with businesses to create real-world solutions to global issues. Through its educational offering, it works with partners around the world to offer relevant, flexible education, which trains students for jobs not even thought of. This connectivity is what sets Southampton apart from the rest; we make connections and change the world. http://www.southampton.ac.uk/

http://www.southampton.ac.uk/weareconnected

#weareconnected
For more information:
Glenn Harris, Media Relations, University of Southampton, Tel 023 8059 3212, email G.Harris@soton.ac.uk, Twitter: @glennh75

www.soton.ac.uk/mediacentre/

Follow us on twitter: http://twitter.com/unisouthampton

Like us on Facebook: www.facebook.com/unisouthampton