Enhancing betavoltaic nuclear battery performance with 3D P^(+)PNN^(+)multi-groove structure via carrier evolution

Betavoltaic nuclear batteries offer a promising alternative energy source that harnesses the power of beta particles emitted by radioisotopes.To satisfy the power demands of microelectromechanical systems(MEMS),3D structures have been proposed as a potential solution.Accordingly,this paper introduces a novel 3D^(63)Ni–SiC-based P^(+)PNN^(+)structure with a multi-groove design,avoiding the need for PN junctions on the inner surface,and thus reducing leakage current and power losses.Monte Carlo simulations were performed considering the fully coupled physical model to extend the electron–hole pair generation rate to a 3D structure,enabling the efficient design and development of betavoltaic batteries with complex 3D structures.As a result,the proposed model produces the significantly higher maximum output power density of 19.74μW/cm^(2) and corresponding short-circuit current,open-circuit voltage,and conversion efficiency of 8.57μA/cm^(2),2.45 V,and4.58%,respectively,compared with conventional planar batteries.From analysis of the carrier transport and collection characteristics using the COMSOL Multiphysics code,we provide deep insights regarding power increase,and elucidate the discrepancies between the ideal and simulated performances of betavoltaic batteries.Our work offers a promising approach for the design and optimization of high-output betavoltaic nuclear batteries with a unique 3D design,and serves as a valuable reference for future device fabrication.

Neodymium and samarium codoped PLZT ferroelectric ceramics for potential betavoltaic nuclear batteries

In this work,neodymium(Nd)and samarium(Sm)codoped lead lanthanum zirconate titanate(PLZT)ceramics were prepared by a high-temperature solid-state method.The samples were characterized by X-ray diffraction,scanning electron microscopy and ferroelectric analysis.Rare earth-doped PLZT ceramics show good phase formation.An appropriate rare earth element doping amount increases the densities of PLZT ceramics and reduces their resistivities,which is due to the role of rare earth elements in grain refinement.However,the increase in the amount of grain boundaries caused by grain refinement also affects domain inversion.Therefore,with increasing doping concentration,the remnant polarization of PLZT gradually decreases,and the doping of rare earth elements also slightly reduces the band gap of PLZT.Under irradiation with an X-ray simulated beta source with a particle energy of 10 keV(between the average energies of the beta particles of^3H and^(63)Ni),the ceramic sheets in this work produce current densities of up to 1.38 nA/cm^2.This indicates that Nd and Sm codoped PLZT ceramics have a certain potential for application in betavoltaic batteries.

Built-in electric field thickness design for betavoltaic batteries

Isotope source energy deposition along the thickness direction of a semiconductor is calculated,based upon which an ideal short current is evaluated for betavoltaic batteries.Electron-hole pair recombination and drifting length in a PN junction built-in electric field are extracted by comparing the measured short currents with the ideal short currents.A built-in electric field thickness design principle is proposed for betavoltaic batteries：after measuring the energy deposition depth and the carrier drift length,the shorter one should then be chosen as the built-in electric field thickness.If the energy deposition depth is much larger than the carrier drift length,a multi-junction is preferred in betavoltaic batteries and the number of the junctions should be the value of the deposition depth divided by the drift length.