To decrease the costs of photovoltaics-generated electricity below $1/Wp installed, the 2012 International Technology Roadmap for Photovoltaics (ITRPV) calls for thinner silicon substrates, less silver metallization per cell, and reduced recombination losses at the front and rear, with cell efficiencies for crystalline silicon between 20% and 24% by 2020. The roadmap emphasizes the need for new cell concepts suitable for achieving high efficiencies on thin wafers. Schottky barrier junction cells can provide both simplified low temperature processing and high efficiencies when Fermi level pinning at the metal-semiconductor interface is prevented. Only recently have both knowledge and processing techniques emerged that result in measured record-high Schottky barrier heights that reflect the known work function differences between metals and silicon. It therefore becomes possible to explore application of these techniques to create an interdigitated back point contact Schottky barrier based silicon solar cell with efficiency greater than 20% and target demonstrating laboratory cells with a process compatible with high volume solar cell manufacturing. This project will elucidate how the atomic-scale modification of the metal-silicon interface affects carrier transport and surface recombination velocity and determining through both experiments and device modeling how this knowledge can be translated into a high efficiency Schottky barrier solar cell with a simplified manufacturing process. This is a new solar cell structure which has been envisioned for decades, but only recently the science and technology have advanced to enable its demonstration. The research is a blend of materials science and electrical engineering with importance in both academia and industry.
The demonstration of a simplified single junction silicon solar cell will help enable silicon photovoltaics to become a major part of the solution to the world?s energy problem. In conjunction with the NSF-DOE ERC for Quantum Energy and Sustainable Solar Technologies (QESST) at ASU, this project will have a clear path for industry input and technology transfer through our industry partners. In addition the project will make a targeted effort to increase the representation of American Indians in science and engineering as well as increase the awareness of local Arizona tribes on photovoltaic technologies.