Leigh T. Canham

Progress towards silicon optoelectronics using porous silicon technology

Abstract We briefly review the performance to date of a variety of porous Si-based discrete optoelectronic devices. Light emitting diodes, waveguides and photodetectors have now been demonstrated, together with a number of non-linear optical effects that could be exploited in electro-optic or all optical modulators. In each case comparison is made with bulk Si devices to identify where exploitation of porosity has already resulted in significant performance gains, or might do in the future. Dramatic progress has recently been made with regard to visible light emitting diodes and efficiencies are now > 104 × higher than those of bulk Si devices. Preliminary studies suggest that porous Si should also be developed for both passive and active waveguiding. Key problems that are still to be addressed with regard to applications are also identified.

Silicon as an Active Biomaterial

The response of a range of porous Si and poly Si films to storage in acellular simulated body fluids is summarised and its implications discussed. It is suggested that the combination of VLSI technology, micromachining and surface microstructuring achievable with silicon, could establish this prominent semiconductor as a very useful biomaterial by the next century. The ‘biocompatibility’ of a variety of silicon microstructures, and even bulk silicon has received surprisingly little study, but now warrants detailed in-vitro and in-vivo assessment.