Researches on the performance of GaN-PIN betavoltaic nuclear battery

The theoretical and experimental investigation work of an in-house produced 63Ni radioisotope-powered gallium nitride (GaN)-based direct conversion (betavoltaic) nuclear battery is described. The GaN-PIN devices with different thicknesses of depletion layer were fabricated, and the thickness of depletion layer and doping concentration of the cell were simulated and optimised. The nuclear battery was tested with 63Ni radioisotope source with different radioactivity density. The test results show that the power density of the nuclear battery can exceed 6 nW/cm2, the open-circuit voltage can reach 1.25 V and the energy conversion efficiency is 2.78%. The radioisotope’s self-absorption effect is explored by Monte Carlo modelling. The series and parallel integrated forms of the two devices are successfully fabricated, and their electrical characteristics are tested. Finally, the temperature effect of nuclear cell is studied preliminarily, the output power of nuclear battery is increasing with the increase of temperature.