High open-circuit voltage betavoltaic cell based on GaN pin homojunction

A high open-circuit voltage betavoltaic cell based on a GaN pin homojunction is demonstrated. A process of doping compensation has been developed to achieve high resistance i-GaN film for betavoltaics. Under 0.5 mCi 63Ni source irradiation, the open-circuit voltage of the fabricated GaN pin homojunction betavoltaic cell was measured as high as 1.65 V. A fill factor of 54% and a 2.7% lower bound on the power conversion efficiency were obtained. The results suggest GaN is a highly potential candidate for the long-life betavoltaic cell.