Quantitative modeling, optimization, and verification of 63Ni-powered betavoltaic cells based on three-dimensional ZnO nanorod arrays

Betavoltaic cells (BCs) are promising self-generating power cells with long life and high power density. However, the low energy conversion efficiency ( ECE ) has limitations in practical engineering applications. Wide-bandgap semiconductors (WBGSs) with three-dimensional (3-D) nanostructures are ideal candidates for increasing the ECE of BCs. This paper proposes hydrothermally grown ZnO nanorod arrays (ZNRAs) for 63 Ni-powered BCs. A quantitative model was established for simulation using the parameter values of the dark characteristics, which were obtained from the experimental measurements for a simulated BC based on a Ni-incorporated ZNRAs structure. Monte Carlo (MC) modeling and simulation were conducted to obtain the values of the β energy deposited in ZNRAs with different nanorod spacings and heights. Through the simulation and optimization of the 3-D ZNRAs and 2-D ZnO bulk structures, the performance of the 63 Ni-powered BCs based on both structures was evaluated using a quantitative model. The BCs based on the 3-D ZNRAs structure and 2-D ZnO bulk structure achieved a maximum ECE of 10.1% and 4.69%, respectively, which indicates the significant superiority of 3-D nanostructured WBGSs in increasing the ECE of BCs.