Demonstration of a 4H SiC betavoltaic cell

A betavoltaic cell in 4H SiC is demonstrated. A p-n diode structure was used to collect the charge from a 1mCi Ni-63 source. An open circuit voltage of 0.72V and a short circuit current density of 16.8nA∕cm2 were measured in a single p-n junction. A 6% lower bound on the power conversion efficiency was obtained. A simple photovoltaic-type model was used to explain the results. Fill factor and backscattering effects were included in the efficiency calculation. The performance of the device was limited by edge recombination.