Demonstration and aging test of a radiation resistant strontium-90 betavoltaic mechanism

Abstract

In this work, a betavoltaic combined with photovoltaic mechanism using strontium-90 as a radioactive source was built up. A transparent yttrium aluminum garnet ceramic doped with a cerium ion is used as an intermediate conversion layer to avoid direct irradiation to a semiconductor conversion device and translates most of the high energy beta particles into photons. The traditional crystalline silicon conversion device with an N⁺PP⁺ junction structure functions as a betavoltaic and photovoltaic conversion device simultaneously. Radiation resistance is demonstrated by a 0.9 MeV electron beam irradiation aging experiment. In the optimized betavoltaic setup with a 0.5 mm transparent yttrium aluminum garnet ceramic, the crystalline silicon conversion device can bear 5 × 10¹⁵ e/cm² by degrading output power less than 15%. Loaded with 1.3 mCi strontium-90, this betavoltaic setup produces a short circuit current of 282 nA, an open circuit voltage of 0.168 V, a fill factor of 0.58, and a total conversion efficiency of 0.32%.