Process Engineering Technology for Manufacture of High-Performance Radiation Detection Semiconductor Materials

C56-03a-273587For national security and non-proliferation missions, there is a need for the development of radiation detectors that simultaneously exhibit good energy resolution, high efficiency, high sensitivity, and good uniformity over an area > 15 cm2 without a need for deep cooling. The development of new materials is seen as a leading option for fulfilling this need. In work by other groups, there is evidence of superior characteristics for halide perovskite materials regarding their use for gamma ray detection. We propose to make improved radiation detectors possible by growth of large, high-quality perovskite crystals and by improved formation of contacts on these materials. By use of new contact materials and engineering of the contact-perovskite interface, we hope to achieve both efficient carrier extraction and very low dark current. In this Phase I program, the team led by Amethyst will show the feasibility of its technical approach for enabling improved gamma ray detectors. There will be 1) growth of perovskites, with an emphasis on crystal quality, 2) synthesis of polycrystalline perovskites from powder, 3) characterization of the perovskites, 4) coating/layering of perovskites with contact materials, and 5) evaluation of the effectiveness of the contacts for both dark current and carrier extraction. Phase I will demonstrate a new contact scheme for a perovskite composition suitable for radiation detection and will generate new characterization results for such a composition. Phase II will be directed at making demonstration devices, which we plan to test in collaboration with DoE laboratories. The work will include improvements in the perovskite material quality and continued development of the contact technology. Phase III will include manufacturing considerations. Metrics set forth by DoE include high material uniformity over > 4 cm length, 80% detector yield, and a cost <$100/cm3 for the perovskite. For the Department of Energy, a successful program will yield more capable detection and imaging of x- ray and gamma ray sources to support nuclear security and non-proliferation. In the commercial sector, there are medical, energy/power, and industrial applications that will benefit. Users in these areas have become dependent on the benefits of semiconductor radiation detectors (compactness, high energy resolution) and will welcome detectors based on lower-cost and more uniform materials. The criticality of radiation detectors in key areas creates a strong payback to society for performance improvements.