Theoretical investigation of high-efficiency GaN-Si heterojunction betavoltaic battery

The wide-bandgap semiconductors, which have the advantages of radiation resistance and high carrier mobility, have gained increased research attention in recent years for the conversion nuclear battery. Nevertheless, when a wide-bandgap semiconductor is used, the collection efficiency and current are reduced, even though the open circuit voltage is increased. In this research, a heterojunction photovoltaic cell is used to increase collection efficiency and power in the betavoltaic battery. A theoretical investigation of the electrical performance has been carried out on Ni-63/GaN and Ni-63/GaN-Si betavoltaic cells. The effects of doping concentration and junction depth on the maximum power are examined. By optimizing the doping concentration and junction depth, a high-efficiency heterojunction betavoltaic microbattery can be achieved. The maximum power is calculated as 22.90 nW/cm(2) using 1 mCi Ni-63 beta source and GaN-Si heterojunction with junction depth of 0.1 mu m and doping concentrations of N-a = 4 x 10(17) cm(-3) and N-d = 4 x 10(16) cm(-3) in the emitter and the base region, respectively.