Design and simulation of GaN based Schottky betavoltaic nuclear micro-battery

•Ni-63 is employed as the pure beta radioisotope source.•The Schottky junction betavoltaic battery is based on the wide-band gap semiconductor GaN.•The total energy deposition of incident beta particles in GaN was simulated by the Monte Carlo method.•A Fe-doped compensation technique is suggested to increase the energy conversion efficiency.

The current paper presents a theoretical analysis of Ni-63 nuclear micro-battery based on a wide-band gap semiconductor GaN thin-film covered with thin Ni/Au films to form Schottky barrier for carrier separation. The total energy deposition in GaN was calculated using Monte Carlo methods by taking into account the full beta spectral energy, which provided an optimal design on Schottky barrier width. The calculated results show that an 8 μm thick Schottky barrier can collect about 95% of the incident beta particle energy. Considering the actual limitations of current GaN growth technique, a Fe-doped compensation technique by MOCVD method can be used to realize the n-type GaN with a carrier concentration of 1×1015 cm−3, by which a GaN based Schottky betavoltaic micro-battery can achieve an energy conversion efficiency of 2.25% based on the theoretical calculations of semiconductor device physics.

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