4H SiC beta-powered temperature transducer

The change in open-circuit voltage of a 4 H SiC pn diode betavoltaic cell in response to temperature was used to sense temperature. A linear sensitivity of 2.7 mV/K was obtained from 24degC to 86degC. This was achieved with only 2.5 muCi of active Ni-63 as the beta-source, giving a short circuit current of 21 pA, low-enough an activity for civilian applications. The measured sensitivity of 2.7 mV/K was lower than the 5.5 mV/K predicted from theory. The 28 GOmega shunt resistance of the betavoltaic cell was used to explain the lower sensitivity. Despite the lower sensitivity than predicted by theory, this work represents a significant improvement over metal thermocouples which typically give <0.1 mV/K.