Investigation of nickel‐63 radioisotope‐powered GaN betavoltaic nuclear battery

Abstract

Summary This work describes the theoretical and experimental investigation of an in‐house produced 63Ni radioisotope‐powered GaN‐based direct conversion (betavoltaic) nuclear battery. GaN p‐n junction device with 1‐mm2 area was fabricated and irradiated by the 63Ni plate source. Short‐circuit current and open‐circuit voltage of the battery were measured, and current‐voltage curves were plotted. The energy stored in battery, maximum power, and efficiency parameters were calculated. Monte Carlo modelling was used to investigate radioisotope's self‐absorption effect, the optimization of semiconductor and source thickness, transport, and penetration of beta particles in semiconductor junction. A large fraction of beta particle energy emitted from 63Ni source is absorbed within 1 μm of the semiconductor junction on the basis of the simulation results. Epitaxial growth of GaN was performed using metal‐organic chemical vapour deposition (MOCVD) system. Monte Carlo simulation with MCNPX was used to determine optimum 63Ni radioactive film thickness. 63Ni film was electroplated on one face of 1‐mm2 copper plate and mounted 1 mm over the semiconductor device. A 63Ni source with an apparent activity of 0.31 mCi produced 0.1 ± 0.001 nA short‐circuit current (Isc), 0.65 V ± 0.0022 open‐circuit voltage (Voc), and 0.016 nW ± 0.0002 maximum power (Pmax) in the semiconductor device. The filling factor (FF) of the betavoltaic cell was 25%, and the conversion efficiency (ɳ) was 0.05%. Finally, experimental results were compared with theoretical calculations.

Design and Analysis of Gallium Nitride-Based p-i-n Diode Structure for Betavoltaic Cell with Enhanced Output Power Density

“…The variation ranges of H p-GaN and H i-GaN were 60–200 nm and 500–900 nm, respectively. The ranges of H p-GaN and H i-GaN values were determined by considering the penetration depth of 17 keV electrons at about 1 μm [ 24 ]. The energy of the e-beam is the average energy of 63 Ni [ 25 , 26 ].…”

Comparison and study of the preparation methods for phosphor layer in nuclear battery

“…The nuclear battery is widely used in severe environments such as outer space and deep sea, because of its small size, light weight, long service life, and stable output power 1‐4 . At present, miniaturized nuclear batteries mainly consist of decay particle conversion mechanism; however, radiovoltaic nuclear battery with direct conversion mode causes severe displacement damage of the semiconductor unit and shortens its service life 5‐8 . The radiation resistance of fluorescent materials is better than semiconductor materials 9,10 .…”

Design and optimization of GaN ‐based betavoltaic cell for enhanced output power density

“…1,2 Gallium nitride (GaN), a wide-band gap semiconductor (E g = 3.4 eV), is regarded as an attractive material for BV cell because GaN-based BV cells can achieve a high energy conversion efficiency and radiation resistance. 3,4 However, the experiment results of the fabricated GaN BV cells based on the vertically p-i-n junction diode [5][6][7][8][9] or Schottky diode 10 exhibited a lower power conversion efficiency than the maximum theoretical efficiency. Recently, since the performance of conventional p-(i)-n structures was mainly investigated with different substrate 11 and effects of physical parameter such as doping concentration and junction depth, 12 researches about novel and creative structure for improving performance are insufficient.…”