Duration: 18 months
The concept of beta voltaic generator is well known, these devices generate electricity by non-thermal radiation conversion, thereby allowing a high conversion yield. Since they rely mostly on a semiconductor coupled to a radioactive source, they are light and compact. Thanks to the recent breakthroughs in high quality ultra-wide bandgap semiconductors, beta voltaic generators regain in visibility. UK, US and Chinese companies are trying to develop such devices using tritium, nickel-63 or even carbon-14 sources. DIAMFAB work since 2021 to develop such generators coupling diamond with tritium. These devices target ultra-low power applications, ranging from 100 nW.cm-3 to, some claims, 100 µW.cm-3. Hereby, we aim to demonstrate the feasibility of a high-power beta voltaic generator, reaching 60 to 110 mW.cm-3 of electricity. Thanks to its intrinsic properties ideal for beta voltaic applications (ultra-wide and indirect band gap, high conversion efficiency, radiation hardened, exceptional charge carrier mobility), the selected semiconductor is diamond. For the radioactive source, we selected strontium-90, as this beta emitter has a 28.9-year half-life and one of the highest energy density for long term application (0.95 W.g-1). Furthermore, 90Sr is available in industrial quantities at high isotopic concentration in nuclear spent fuel. This material is today considered as a waste. We hope to develop a product with a service life of between 30 and 60 years. We estimate the generator initial power could reach 60 to 110 mW.cm-3 of electricity, as well as 0.5 to 1 W.cm-3 of heat. This project will be led by DIAMFAB, with the support of STMicroelectronics and Orano. DIAMFAB is a start-up specialized in diamond semiconductor and diamond based components manufacturing. STMicroelectronics is a Franco-Italian multinational company, which designs, manufactures, and markets electronic chips. Orano SA is a multinational company specialized in nuclear fuel cycle management.
