High Efficiency Floating Junction Gallium Arsenide Solar Cell

AstroPower proposes to develop a new ultra-thin gallium arsenide solar cell for space applications, that will result in significantly higher performance compared to conventional gallium arsenide and silicon solar cells. This design incorporates a "floating" junction on the front of the ultra-thin solar cell and a collecting junction at the back of the device. This design will significantly decrease minority carrier recombination compared to conventional GaAs heterostructure solar cells due to the active passivation effects associated with carrier injection from the front floating junction. A shallow front floating emitter coupled with an all back contact design that eliminates grid shading will significantly increase the spectral response. The result of the floating junction design will be a revolutionary increase in open circuit voltage and short circuit current. Fabrication costs will decrease when compared to conventional GaAs solar cells because a monolithic metallization sequence and a non-conducting reflector technology will eliminate processing steps associated with conventional solar cell processing. Light-trapping and an adhesiveness coverslide technology will be incorporated into the floating junction design to increase efficiency, durability and specific power. The specific power for this solar cell is projected to be 3621 W/kg for an AMO efficiency of 25%. This Phase I can lead to the deployment of high efficiency ultra-thin GaAs solar cells in the space environment. The proposed solar cell design can have a significant impact on the longevity, cost effectiveness and power generation capabilities of space power supplies. Dual use applications include solar cell concentrator arrays, detectors for solid state spectrometers, microwave devices and better heat dissipation for GaAs high-power IC chips and surface emitting laser arrays. Other applications include integrated logic components, LEDs, LED displays, flat screen display drivers, waveguides and related devices.