Comprehensive Study on p-n Junction and Schottky Barrier Betavoltaic Battery with ¹⁴C Beta-Emitting Source

In this work, a nuclear battery with a ¹⁴C source was developed to improve the electrical properties of betavoltaic batteries. The betavoltaic battery energy converters containing different semiconductors, such as Ga₂O₃, GaAs, GaN, GaP, Si, and SiC, were evaluated to convert the ¹⁴C radioisotope source energy into electrical energy. The electrical output properties of the betavoltaic battery were established through numerical calculation for two structures of the p-n junction and Schottky barrier (with Ag, Al, Au, Mo, Ni, Pd, and Pt as Schottky metals). The optimum thickness of the ¹⁴C radioisotope and its energy deposition distribution within the semiconductors were determined using the Monte Carlo method.

In the betavoltaic battery with the p-n junction configuration, the optimized doping concentration yielded a maximum output power density and energy conversion efficiency of 20.97 μW·cm⁻² and 7.20%, respectively, for the Ga₂O₃ semiconductor. In contrast, these parameters for the Pt-Si Schottky barrier betavoltaic were obtained at 1.34 μW·cm⁻² and 0.46%, respectively, with the 20-nm thickness of the Pt Schottky metal layer and a doping concentration of 10¹⁵ cm⁻³. These findings are valuable and helpful for assembling reasonable betavoltaic batteries.