Overcoming Optical-Electrical Grid Design Trade-offs for cm²-Sized High Power GaAs Photonic Power Converters by Plating Technology

The optimization III-V based photovoltaic cells requires resolving the trade-off between optical losses due to grid shading and electrical losses due to series resistance. In this work the boundary conditions of this optimization problem are overcome by increasing the grid line height. Contrary to few µm high evaporated metal grid lines, distributed circuit modeling of 1-cm² GaAs photonic power converters suggests that best performances require 15-µm high grid lines, especially for high current operation in the 1 to 10 A cm-2 range. A silver plating process has successfully been implemented into the fabrication scheme of respective devices. Current-voltage measurements under intense illumination at currents up to 35.8 A demonstrate a fill factor above 80% at a monochromatic input power of 62.6 W, which results in a maximum power output of 35.5 W from the 1-cm² photovoltaic cell. This development enables optical power links with largely increased power densities and thus reduces material demand of previous semiconductors as well as costs.