SBIR Phase I: High Efficiency Low Cost Laser Anneal for Manufacture of CdTe Solar Cells

This Small Business Innovation Research Phase I research project proposes to enhance the manufacturing process for solar cells that are made from the compound semiconductor materials CdS and CdTe. This would result in increased manufacturing flexibility, lower production costs, and photovoltaic modules with higher sunlight to electrical energy conversion efficiencies. Current thin film CdTe based photovoltaic manufacturing requires two post-deposition heat treatments to achieve high energy conversion efficiencies. These anneals are currently done by heating the entire cell and this can cause undesirable side effects. The heat accelerates diffusion especially along grain boundaries and can create unintentional micro non-uniformities that lead to performance degradation. This proposal seeks to develop a laser based anneal manufacturing process that selectively heats only the intended thin film layers and produces higher efficiency lower cost CdTe solar cells. Photovoltaic modules directly convert sunlight into electricity silently without generating any pollution or greenhouse gases. Once the capital investment is made to install a photovoltaic system, the cost of generating the electricity is essentially zero because its fuel"", the sunlight, is free. A house roof partially covered with photovoltaic modules can usually generate enough electricity on average to provide for all of the household electrical needs. This distributed household energy independence has intrinsic appeal for many consumers and with net metering it insulates them from fluctuating retail electricity prices.