First principles study on the time-related properties of 4H-32SiC as energy converting material of betavoltaic battery

The radioactive 4H-32SiC is applied as energy converting material to fabricate high performance betavoltaic batteries. The time-related component change is considered, and the structural, stability and electrical property changes are calculated by Density Functional Theory (DFT). As time goes by, the number of 32Si atoms decrease exponentially while the concentration of 32S increases gradually. The Si63PC64 configurations have smaller lattice constants, while the lattices of Si62PSC64 configurations are larger. All Si63PC64 and Si62PSC64 configurations have very small bandgaps indicating the metallic behavior. This suggests that the betavoltaic battery with 4H-32SiC is likely to transform into a Schottky diode over time.