SiC/Si-Based Converter of C-14 Beta Decay Energy

Results of a study of betavoltaic energy converters and specifically of the devices on SiC/Si based heterostructures using the radionuclide 14C as a source of beta radiation are presented. The Si14C/Si semiconductor chip integrates in a natural way a beta electron injector and an energy converter based on a homo- or heterojunction, which increases the specific power and provides radiation safety by self-shielding through a 10–20 µm thick SiC layer, due to self-absorption effective self-containment of radiation within the integrated semiconductor structure. The achievable power density is 0.3 µW/cm3 with a silicon carbide thickness of 0.4 µm; the maximum short-circuit current density is 900 nA/cm2, and efficiency is 21.31%. The results of modeling and experimental studies indicate that a silicon carbide film doped with a radioisotope on a silicon substrate features improved output characteristics of the energy converter due to the optimal distribution of non-equilibrium charges and dislocation gettering effects of the 14C atoms in the inner layer of the converter structure with a molecularly integrated injector. The importance of betavoltaics is that it synchronizes the achievements of microelectronics and energy sources for its autonomous functioning based on the conversion of energy of high specific density. This provides an option of delayed switching of software in an electronic device corresponding to the half-life period or accumulation of information in databases operating on the basis of an integrated “IC chip–power source”. This technology enables delayed activation of electronic systems via integrated supercapacitor buffering, facilitating energy-aware scheduling in applications from structural health monitoring to lifetime-guaranteed medical implants.