Temperature Dependence of Betavoltaic Cell Performance of Diamond pn Junction Diode

Temperature dependence of the energy conversion efficiency of diamond pn junction betavoltaic cells was evaluated. We fabricated pseudo vertical diamond pn junction diode and characterized its energy conversion efficiency under electron beam irradiation from 5-300 K. The diamond pn junction diode exhibits energy conversion efficiencies of 18-24% at 150-300 K, which is more than twice as high as those of silicon PiN diode. On the other hand, below 100 K, the energy conversion efficiency of the diode significantly drops due to the increase of series resistance of diamond. Above 150K, the diamond pn junction diode presents smaller temperature dependency on energy conversion efficiency than that of silicon diode, which would make diamond pn junction betavoltaic cells, a promising device for energy harvesting in remote sensing devices over a wide temperature range except in the cryogenic region.