This SPIE Defense & Security paper by Handel examines quantum 1/f noise in all-epitaxial metal-semiconductor diodes. The research analyzes low-frequency noise in Schottky barrier diodes fabricated entirely by epitaxial growth techniques without requiring external metal deposition, investigating how quantum 1/f noise mechanisms differ in these structures compared to conventional diodes, with applications to millimeter-wave mixers, detectors, and frequency multipliers where low noise performance is critical for radar and communications systems.