APPLICATIONS OF TECHNOLOGY:
- Photovoltaic panels
- Higher throughput, lower capital costs
- Compatible with roll-to-roll processing
- Low-cost metal foil substrates
Berkeley Lab researcher Maxwell Zheng and colleagues have developed technologies for economic, high volume production of high optical quality polycrystalline indium phosphide (InP), with optical properties nearly identical to those of InP on single-crystal wafers, on low cost metallic substrates. The technologies reduce costs at both the growth stage and in downstream processing.
Specifically, the researchers demonstrated that polycrystalline InP can be grown on metal foils using a closed space sublimation (CSS) process. Effective transfer of the InP source to the foil substrate is made possible in CSS by the small (~2 mm) gap between source and substrate. This technology is easily scalable and adaptable for other technologies, such as photo-electrochemical hydrogen production.
In addition to lower cost, CSS offers superior spatial control and crystalline morphology control, so that the properties of InP devices can be specifically tailored. By tuning the growth conditions, InP nanowires, patterned crystals, and polycrystalline films can be obtained with CSS. The team also used metal organic chemical vapor deposition (MOCVD) to grow InP on metal foil.
InP is a III-V semiconductor, a class of materials that has high absorptivity and mobility, with ideal band gaps for photovoltaic devices. However, use of InP has been constrained because indium is a rare element much costlier than silicon. Currently, leading photovoltaic III-V solar cells are fabricated by complex epitaxial growth processes and epitaxial layer transfer techniques.
DEVELOPMENT STAGE: Bench scale prototype.
STATUS: Patent pending. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Zheng, M., Yu, Z., Seok, T.J., Chen, Y-Z., Kapadia, R., Takei, K., Aloni, S., Ager, J.W., Wu, M., Chueh, Y-L., Javey, A. “High optical quality polycrystalline indium phosphide grown on metal substrates by metalorganic chemical vapor deposition,” Journal of Applied Physics 111, 123112 (2012).
Kiriya, D., Zheng, M., Kapadia, R., Zhang, J., Hettick, M., Yu, Z., Takei, K., Wang. H-H. H., Lobaccaro, P., Javey, A. “Morphological and spatial control of InP growth using closed-space sublimation.” Journal of Applied Physics 112, 123102 (2012).
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
Thinner Film Silicon Solar Cells, IB-2564
REFERENCE NUMBER: IB-3173, IB-3238