Heterojunction betavoltaic Si14C-Si energy converter

Abstract

A potential opportunity to improve the integrated betavoltaic batteries and low-power cells performance is the radionuclide-activation method, which is an integrated combination of an injection source and an energy converter in the one material. Energy converters that contain an activated SiC thin film as the Si14C-Si barrier heterojunctions energy converter in betavoltaic cell are considered. The Si14C-Si heterojunction is positioned as by 14C beta source doped direct energy converting material two-in-one, for the device structure with an emitter of Si14C with optimized thickness is 0.4μm and the doping concentrations of N-SiC/p-Si are 15.7÷15.9×1017/16.2×1017÷∼1019cm−3. To ensure efficient operation of a betavoltaic element, the mathematical model determines: the short circuit current density is up to 900 nA cm−2, the open circuit voltage is up to 1.21 V, the fill factor is 0.9, the maximum output power density is up to 300 nW cm−2, the conversion efficiency is up to 16% and up to 0.5 V voltage per load in the experiment. The calculation and experimental verification results indicate that the Si14C-Si structure improved output performance of the nuclear cell by reducing the radioactive source self-absorption energy losses and due to better energy deposition distributions of inner injector. The results are valuable for optimizing the integrated betavoltaic elements production.