Terahertz generation in submicron GaN diodes within the limited space-charge accumulation regime

The conditions for microwave power generation with hot-electron transport are investigated in a submicron GaN diode when it operates in the limited space-charge accumulation (LSA) mode. Applying a transport model based on the local quasistatic approximation, the analysis shows that the nitride diodes can support the LSA mode of oscillation in the terahertz-frequency range. For a 100nm n-GaN diode with a cross section of 500μm2 and the electron density of 1×1017cm−3, the generated microwave power is estimated to be as high as ≈0.6W with the corresponding dc-to-rf conversion efficiency of ≈9% and the negative differential resistance of ≈−1.3Ω; which thus provides an efficient mechanism to achieve very high-frequency microwave generation in the nitrides.