Structure design and performance optimization of GaAs based betavoltaic microbattery using solid-state tritium source

Betavoltaic microbatteries have shown a great promising potential in military and commercial applications due to their attractive characteristics of easy integration, long lifetime and superior adaptability. However, improvement of both energy conversion efficiency and output power has been a big challenge. In this paper, we proposed a GaAs based betavoltaic microbattery using solid-state tritium source. The influences of structural parameters of solid-state tritium source and GaAs semiconductor transducer, the self-absorption and surface recombination effects and doping concentrations on the output performance of the betavoltaic microbattery were analyzed by the Monte Carlo simulation and Matlab code. The electrical performance of the betavoltaic microbattery was evaluated and optimized. The simulation results showed that under an illumination of 0.2 Ci titanium tritide (TiT₂) film, the betavoltaic microbattery displayed a maximum output power of 39.8 nW and energy conversion efficiency of 0.58% with an open-circuit voltage of 0.62 V, a short-circuit current of 76.9 nA, and a high filling factor of 0.83. It is noted that the thickness of solid-state tritium source and reverse saturation current of GaAs semiconductor transducer have important influences on output performance and should be reasonably reduced.