Silicon carbide alphavoltaic battery

The development of new wide bandgap, highly radiation resistant semiconductors, such as SiC, may make it possible to use an inexpensive alpha particle emitting isotope to construct high efficiency, long lifetime radioisotope power sources. To study the possibility of producing an alphavoltaic battery, SiC photodetector diodes were irradiated with 5.5 MeV alpha particles from the radioisotope Am-241. Further studies of the radiation resistance of SiC were made using 1 MeV electrons in an accelerator facility. During the irradiation, the power output of the SiC cell was monitored and its degradation measured. Although the initial power output was considerable, a rapid decay of the power output occurred. Basic studies of the radiation resistance of SiC were also made using deep level transient spectroscopy (DLTS). Six deep levels were found in both the unirradiated and irradiated SiC diodes. The carrier removal rate of 2.46 per 1 MeV electron measured here in SiC is very similar to the value of 2.85 per 1 MeV electron measured in InP, another highly radiation resistant semiconductor. The rapid degradation in output and considerable carrier removal rates observed here suggest that SiC has a radiation resistance similar to but not better than other radiation resistant semiconductors such as InP. The considerable initial output of the SiC battery was however, very encouraging, and further developments in SiC technology may make it possible to reduce the radiation damage rate in this application.