Achieving 2.1% Efficiency in Alpha-Voltaic Cell Based on Silicon Carbide Transducer

Abstract

Alpha-voltaic cell is a type of micro nuclear battery that provides several decades of reliable power in the nanowatt to microwatt range, supplying for special applications where traditional chemical batteries or solar cells are difficult to operate. However, the power conversion efficiency of the alpha-voltaic cells reported are still far behind the theoretical limit, making the development of alpha-voltaic cell challenging. Developing advanced semiconductor transducers with higher efficiency in converting the energy of alpha particles into electric energy is proving to be necessary for realizing high-power conversion efficiency. Herein, we propose an alpha-voltaic cell based on SiC PIN transducer that includes a sensitive region with an area of 1 cm², a width of 51.2 μm, and a charge collection efficiency of 95.6% at 0 V bias. We find that optimizing the unintentional doping concentration and crystal quality of the SiC epitaxial layer can significantly increase the absorption and utilization of the energy of alpha particles, resulting in a 2.4-fold enhancement in power conversion efficiency compared with that of the previous study. Electrical properties of the SiC alpha-voltaic cell are measured using an He-ion accelerator as the equivalent α-radioisotopes, with the best power conversion efficiency of 2.10% and maximum output power density of 406.66 nW cm⁻² is obtained. Our research makes a big leap in SiC alpha-voltaic cell, bridging the gap between micro nuclear batteries and practical applications in micro-electromechanical systems, micro aerial vehicles, and tiny satellites.