Strain set to improve silicon’s performance in optoelectronic applications

The research, reported in Nature Materials, describes how the team has engineered the electronic band structure of laser crystallised silicon photonic devices in order to overcome one of the key challenges of using silicon in data communications. The technique, developed for the ORC's silicon optical fibre platform, shows that it is possible to crystallise the core material completely, whilst including large stresses to modify the optoelectronic properties. In this way, bandgap reductions from 1.11eV to 0.59eV are realised, enabling optical detection at wavelengths of up to 2100nm. 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 Noel Healy, lead researcher, said: "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.