UC Davis ECE and Lawrence Livermore Lab’s National Ignition Facility have been awarded a three-year research grant from the U.S. Department of Energy.
The research -- “Germanium Photodiode Arrays for Hard X-Ray Imaging” -- targets design, fabrication and measurement of pixelated arrays of ultra-fast vertical photodiodes, which can be bonded to a radiation-hard CMOS read-out circuit for backside-imaging up to 70 keV xrays (“hard” X-rays) with a 1 nano-second response time.
The use of in-situ grown epitaxial germanium with hetero-junction Si-Ge anodes and cathodes, combined with a “graded-base” absorption layer, will potentially increase the quantum efficiency by almost a factor of 10 over current imagers, allowing for a significant improvement in image resolution and lower noise, without sacrificing response speed, when compared to current technology.
At UC Davis, this research will potentially engage multiple graduate students who will work with Professor Hunt on the design, fabrication and measurement of the experimental devices. If successful, this imager technology can be used to help develop laser-fusion technology for long-term, sustainable and clean energy production.