Description: To address the NASA GSFC need for significant improvements in wide bandgap materials and detectors for UV applications, Physical Optics Corporation (POC) proposes to develop a new AlGaN nanowire photocathode for Silicon Microchannel Plate solar-blind photodetector fabricated directly on the MCP entrance plane. This innovative photocathode and the technology of its growth on the Si microchannel plate enables us to meet NASA requirements for windowless operation in the FUV range with high quantum efficiency, low noise, radiation-hardness, reliability, and potentially low cost. In Phase I, POC demonstrated the technology of GaN and AlN nanowire growth by Hydride Vapor Phase Epitaxy and investigated the properties of nanowire surfaces. In Phase II, POC will optimize this technology for fabrication of an AlGaN nanowire photocathode on a silicon MCP structure and demonstrate photodetector operation in the FUV range. This innovative, efficient, solar-blind, and radiation-hard UV photodetector with low background noise and a large sensing area will offer NASA capabilities to design new instrumentation with improved sensitivity and spatial or spectral resolution for FUV and UV instruments for several missions devoted to a better understanding of the origin of the Universe and its evolution to modern form.

Benefits: Military applications for detectors with new photocathode include missile plume detection, fire detection, and detection of biochemical agents and many other scientific instruments. The higher quantum efficiency and extended spectral coverage of UV spectrum will facilitate development of new, more sensitive instruments for medical and industrial applications.

Future NASA applications of Si-based Microchannel Plate photodetectors with AlGaN NW photocathodes fabricated directly on the entrance plate include several missions such as THEIA, NWO, ATLAST, a cosmic web probe, and others. The highly sensitive, solar-blind, low noise, radiation-hard detectors for the FUV region (below 100 nm) will open new opportunities in the investigation of the evolution of the Universe, planet finding, the investigation of Sun-Earth interactims, etc.