Silicon Photonics

We are investigating the physics of silicon nanocrystals (“quantum dots”) embedded in silicon oxide.

Fibre-optic communication is used to transmit data at high speeds using light. There is a drive to develop all-optical processing, eliminating the conversion between light and electrical signals, and taking advantage of the superior speed that all-optical processing can offer. It is desirable that this capability be developed in silicon, rather than in more exotic materials, for reasons of materials cost, and compatibility with the existing highly evolved silicon processing techniques that have been developed over ~5 decades.

The vision of an all-silicon optical chip is hampered by the lack of a suitable silicon-based light source. A promising candidate for this role is silicon nanocrystals (Si-nc) formed in a matrix of silicon oxide. We have grown Si-nc by ion implantation and annealing, and characterized them by a number of techniques, to study the physical processes involved in the growth, and to relate that to the mechanisms of luminescence (including quantum confinement in the Si-nc, which are about 3 nanometres in diameter).