The development of thin-film, silicon-on-ceramic solar cells, made by chemical vapor deposition of silicon on a glass-ceramic substrate, would solve the cost and feedstock problem for commercial solar power production. This is being accomplished through the development of a low-cost, deposition technique combined with a high performance, solar cell design that will have a significant effect on the availability and cost of solar cells. In Phase I, 10 to 30-micron thick layers of silicon were deposited on low-cost ceramic substrates by atmospheric-pressure, trichlorsilane chemical vapor deposition. These silicon-on-ceramic films were recrystallized to achieve minimum grain sizes in excess of 1mm and record high, short-circuit current densities of 29.3 mA/cm2. Another important accomplishment was the attainment of high currents, attributable to an exceptionally high degree of light being trapped from the reflective ceramic and the excellent back-surface passivation at the silicon-ceramic interface. Phase II will be directed toward large-scale, high-throughput, chemical-vapor deposition for producing commercial quantities of the silicon-on-ceramic solar cells. Efficiencies greater than 17% at laboratory-scale (1cm2) and greater than 15% in a 10-cm x 10-cm solar cell will be demonstrated.
Commercial Applications and Other Benefits as described by the awardee: The silicon-on-ceramic material should substitute for silicon wafers or sheets in solar cell production lines, producing a commercial product for the multi-billion dollar photovoltaic market. Substantial cost reductions can be realized by eliminating the need for bulk silicon.
