Power Generation: Focus Areas
Inorganic Photovoltaics
Our expertise in solar cells dates back to the 1980s, when our scientists, in collaboration with researchers at North Carolina State University, pioneered the first tunnel-junction cascade solar cells in the GaAs-AlGaAs materials system. This set the stage for the development of GaInP2-GaAs cascade solar cells in early 1990s by the National Renewable Energy Laboratory.
We also developed the first p-on-n GaInP2-GaAs-Ge, 3-junction cascade solar cell that was transitioned to industry for further advancement and large-scale manufacturing. This technology is being used in modern satellites.
Today, we are researching Si, SiGe alloy, Si/Ge superlattice, Si/Ge quantum dot solar cells through an innovative combination of nanoscale materials, device structures, and processing, along with the use of surface plasmonics to enhance long wavelength photon absorption. Working with Duke University researchers who are developing organic solar cells, we are investigating the integration of low-cost inorganic solar cells to form hybrid inorganic-organic photovoltaic structures that are 15% more efficient than current technology.
Contact: Rama Venkatasubramanian
Research Citations
Venkatasubramanian, R., O'Quinn, B.C., Siivola, E., Keyes, B., & Ahrenkiel, R. (1997). 20% (AM1.5) efficiency GaAs solar cells on sub-mm grain-size poly-Ge and its transition to low-cost substrates. Twenty Sixth IEEE Photovoltaic Specialists Conference, Anaheim, CA, 29 September - 03 October 1997, 811-814. Lasich, J.B., Cleeve, A., Kaila, N., Ganakas, G., Timmons, M., Venkatasubramanian, R., Colpitts, T., et al. (1994). Close-packed cell arrays for dish concentrators. IEEE First World Conference on Photovoltaic Energy Conversion, conference record of the Twenty Fourth IEEE Photovoltaic Specialists Conference - 1994 : Waikoloa, Hawaii, December 5-9, 1994., (2):1938-1941. Venkatasubramanian, R., Timmons, M.L., Hutchby, J.A., Field, H., & Emery, K. (1994). GaAs and Al0.2Ga0.8As solar cells with an indirect-bandgap Al0.8Ga0.2As emitter-heterojunction cells. IEEE First World Conference on Photovoltaic Energy Conversion, conference record of the Twenty Fourth IEEE Photovoltaic Specialists Conference - 1994 : Waikoloa, Hawaii, December 5-9, 1994, (2):183921842. Venkatasubramanian, R., Timmons, M.L., Colpitts, T.S., Hancock, J., Hills, J., Hutchby, J.A., et al. (1993). Development of high-efficiency Al0.2Ga0.8As solar cells and interconnect schemes for Al0.2Ga0.8As/Si mechanically-stacked cascade cells. Twenty Third IEEE Photovoltaic Specialists Conference--1993, Louisville, KY, May 10-14, 1993, 752-756.