P-N and P-i-N junction silicon microwire arrays for solar energy conversion

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Annual global energy demands are projected to rise by roughly a quarter between now and 2040 (International Energy Outlook, Sept 2017, Dept. of Energy, USA). Renewable energy sources and reliable energy storage are critical to meeting these energy needs in northern, remote areas of Canada and worldwide. Alternatives to renewing or building costly infrastructure, especially nuclear installations, are desirable. Sunlight is the principal renewable energy resource - in a handful of hours the total solar energy incident on the globe exceeds our annual energy demands. Despite great strides in photovoltaic and battery technology, increasing energy storage density and reducing cost remain challenges. In addition, the raw materials for these technologies rely heavily on highly-restricted supply chains. Harnessing and storing solar energy in chemical bonds represents a compelling quest that resolves the issue of energy storage density. Using earth-abundant materials to capture solar energy enacts the most basic tenets of resource stewardship while benefitting remote (northern) and developing communities.******The research in this proposal will develop key technologies for solar-based fuel generation: storing energy in the simplest chemical bond (hydrogen) or converting carbon dioxide into a useable fuel. Using a variant of chemical vapor deposition, earth-abundant silicon will be used to fabricate high-fidelity single-crystal microwires with excellent performance characteristics at low cost. My team will fabricate multicomponent silicon microwires that incorporate a transition from a boron-doped region to a phosphorus-doped region. The electrical characteristics of this transition region will open up new design pathways for prototype solar fuel generation components. When integrated into a solar collector, these new silicon microwires will absorb energy from sunlight and drive a chemical reaction, such as splitting water into hydrogen and oxygen gas or reducing carbon dioxide into a carbon fuel. Ultimately, these new solar-powered fuel generating devices will address critical energy needs, particularly in developing and remote communities.