Betavoltaic battery conversion efficiency improvement based on interlayer structures

Significant differences among the doping densities of PN junctions in semiconductors cause lattice mismatch and lattice defects that increase the recombination current of betavoltaic batteries. This extensively decreases the open circuit voltage and the short current, which results in low conversion efficiency. This study proposes P⁺PINN⁺-structure based betavoltaic batteries by adding an interlayer to typical PIN structures to improve conversion efficiency. Numerical simulations are conducted for the energy deposition of beta particles along the thickness direction in semiconductors. Based on this, ⁶³Ni-radiation GaAs batteries with PIN and P⁺PINN⁺ structures are designed and fabricated to experimentally verify the proposed design. It turns out that the conversion efficiency of the betavoltaic battery with the proposed P⁺PINN ⁺ structure is about 1.45 times higher than that with the traditional PIN structure.