SpectraWatt, a Hillsboro, OR-based maker of photovoltaic cells, received a $500,000 contract from the National Renewable Energy Laboratory yesterday. Part of the American Recovery and Reinvestment Act, the contract is for the company to develop ways of improving solar cells without changing current manufacturing processes. SpectraWatt was one of 13 companies to receive money from NREL, the ultimate goal being to speed up the commercialization of solar energy technologies.