Optical hyperdoping: Extending silicon's reach

Silicon is the world's most widely used semiconductor. As the building block of a photovoltaic cell, silicon offers a combination of stability, efficiency, and manufacturability currently unmatched by any other material. However, as an indirect absorber of light, thick layers of highly-pure, expensive material are required for efficient light absorption and charge collection. Furthermore, silicon does not absorb in the infrared, a spectral region that contains about a quarter of the sun's radiation. In this talk, I will discuss optical hyperdoping, a non-equilibrium laser-doping technique we have been developing for enhancing the optoelectronic properties of silicon. Our preliminary work has demonstrated this technique's promise for developing a new generation of silicon photovoltaics: enabling absorption in dramatically thinner layers and extending the useful spectral range of silicon into the infrared.