SBIR-STTR Award

We propose a research and development path that leads to the creation of triple-junction, high efficiency (30%, and greater in time) III-V cells on 200mm Si substrates, manufactured in a volume-scalable 200mm silicon manufacturing infrastructure. This combination of efficiency, weight, and cost is not possible with any other technology. Our estimates show that specific weight, cost per W, and specific cost of >2000 W/kg, $50/W, and 8x10^4 $/kg, respectively, are achievable within a 5-year time frame. In addition, this advance would alter the business models for delivering high efficiency solar. By being able to access low cost silicon manufacturing infrastructure, scaling demand requires much less capital and time. Thus, demand spikes and access to high volumes of cells can be accommodated using this technology platform for high efficiency solar.

Keywords:
Solar, Photovoltaics, High Efficiency, Iii-V/Si

This proposed Phase II program will deliver a lightweight triple-junction solar cell that eliminates the current-matching bottleneck of current state-of-the-art InGaP/GaAs/Ge cells on Ge. This will be achieved by constructing a triple junction structure on the lattice constant of SiGe, allowing the integration of semiconductors with bandgaps that are optimized for the best possible triple-junction efficiency. The cell design proposed for Phase II has a practical achievable efficiency of 47% (AM1.5 spectrum without concentration), far exceeding the current record of 32% for the same illumination conditions. III-V cell development on the SiGe lattice constant is a natural direction for 4Power’s substrate platform which already utilizes SiGe graded buffers. This strategy for optimized solar cell efficiency is fully compatible with our Si-encapsulated cell technology demonstrated in Phase I. The multijunction cell that will be developed in Phase II will incorporate both Si encapsulation and uniquely accessible optimum bandgap profiles such that high volume/low cost production of ultra-high specific power cells in a Si-compatible manufacturing environment is enabled.

Keywords:
Solar, Photovoltaics, High Efficiency, Iii-V/Si