Tunable Gunn oscillations in a top-gated planar nanodevice

The frequency of a Gunn diode is usually determined by the length of its oscillation channel, hard to be change after the device has been fabricated. We show that in a top-gated planar nanodevice the frequency of Gunn oscillations can be conveniently increased, i.e. tuned by the top-gate bias. Ensemble Monte Carlo (EMC) simulations indicate that the achieved maximum frequency reaches 1 THz, about three times of that of an un-gated device. Moreover, the tunable frequency-range also increases with the length of the top-gate, resulting in a widest range of ∼0.7 THz. Detailed analysis of the Gunn-domain dynamics shows that this tunable effect is related to the simultaneous formation of multi-domains, which are excited by the top-gate induced non-uniformed electricfield along the oscillation channel.