Description:
University of Oregon researchers are manufacturing GaAs in an improved method for photovoltaic devices
The high balance-of-system costs of photovoltaic (PV) installations indicate that reductions in cell costs per watt alone are likely insufficient for PV electricity to reach grid parity unless energy conversion efficiency is also increased. Technologies that yield high-efficiency cells (e.g., greater than 25%) and maintain low costs are needed. GaAs and related III-V semiconductors are used in the highest-efficiency, single- and multi-junction photovoltaics, but the technology is too expensive for non-concentrated terrestrial applications. This expense is due in part to the inability to modify conventional methods, such as metal-organic chemical vapor deposition (MOCVD), in a manner that can produce commercial/industrial scale products at a low cost. MOCVD uses expensive reactors and uses toxic and pyrophoric gas-phase precursors such as arsine and trimethyl gallium, respectively. There exists a need in the art for methods and devices for making GaAs films having desired electronic properties in a scalable and cost efficient manner.
The excellent optoelectronic properties of GaAs make it an attractive material for solar energy conversion. Unfortunately, the scalability of GaAs photovoltaics is limited by the high cost of metal-organic chemical vapor deposition (MOCVD), which employs toxic and pyrophoric gas-phase precursors.
This invention outlines an alternative method of producing GaAs photovoltaics, specifically, a close-space vapor transport (CSVT) technique for depositing GaAs that uses bulk GaAs as the only precursor. This method eliminates the inclusion of toxic and pyrophoric gas phase starting materials, thereby providing a cheaper, safer, and scalable method of manufacturing GaAs photovoltaics and photoelectrode devices.
For more information, see patent # 9,368,670.