Radioisotope power sources offer a compelling alternative to batteries for applications where recharging or replacement is impractical such as deep-sea instrumentation, long-duration space missions, and other remote or hazardous environments. This work presents a coupled simulation framework combining Geant4 radiation transport modeling with Synopsys TCAD device simulation to evaluate radiovoltaic energy conversion across three semiconductor device architectures. Geant4 simulations characterize how alpha and beta particles interact within each device. These energy deposition profiles are then coupled with TCAD device simulations to evaluate short-circuit current density, open-circuit voltage, and fill factor across the full source energy range and layer thickness sweep. The results quantify diminishing returns in short-circuit current density with increasing intrinsic layer thickness. These findings offer design guidance for radiovoltaic devices intended for extreme or inaccessible environments.

Richville Fagaragan is a M.S student in Electrical and Computer Engineering at the University of Hawaii at Mānoa. He earned his B.S. in Electrical Engineering from Hawaii Pacific University in 2023. His current research centers on studying radiovoltaics.