CMOS-Enabled Interdigitated Back-Contact Solar Cells for Biomedical Applications

We demonstrate a 980-nm laser-driven CMOS-enabled interdigitated back-contact (IBC) solar cell for biomedical applications. The design of this device leverages from the CMOS process to allow 2-D junction formation and uniform series resistance, but suffers from poor minority carrier properties in bulk substrate. This issue is partially solved in this paper by thinning down the substrate to 60 μm, leading to an ultimate efficiency of 15%. After inserting an emulated tissue loss, an 1.67-mm2IBC solar cell is capable of generating an electrical power of 159 μW under a concentrated illumination intensity of 10 mW, which is within the conservative limit to human skin.