Research on the basic understanding of high efficiency in silicon solar cells

This report presents results of research designed to develop a basic understanding of high-efficiency silicon solar cells and achieve cell efficiencies greater than 17% by employing innovative concepts of material preparation, cell design, and fabrication technology. The research program consisted of a theoretical effort to develop models for very high-efficiency cell designs, experimental verification of the designs, and improved understanding of efficiency-limiting mechanisms such as heavy doping effects and bulk and surface recombination. Research was performed on high-lifetime float-zone silicon, the baseline materials, low-resistivity gallium-doped czochralski silicon, and boron-doped float-zone silicon.