Electron emission GaN-AlGaN microwave transit-time diode

Microwave impedance of a diode based on electron emission GaN micro-cathode with AlGaN single-layer coating and electron transit in vacuum is studied. The investigations have indicated negative conductance (NC) of the diode in terahertz frequency range. The NC takes place when resonant electron emission occurs through double barrier quantum structure (DBQS) formed by cathode potential profile at certain electric field and parameters of AlGaN layer. Dependence of the NC spectrum on cathode coating parameters is investigated.