Simulation investigation of multiple domain observed in In0.23Ga0.77As planar Gunn diode

• Tunability of oscillation frequency in planar Gunn diode can be achieved through varying the applied voltage.
• Multiple oscillations in planar Gunn diode rely on the non-uniform metallic contact configuration.
• Single oscillation can only be observed in single channel configuration.

A numerical study for an AlGaAs/InGaAs-based quantum well structure planar Gunn diodes was performed by initially proposing imperfect metallic contacts that can introduce multiple anode–cathode spacings caused by etching process during the fabrication. Through Fast Fourier transform (FFT) algorithm, the result reveals that, at moderate bias voltage above the threshold, multi-channel planar Gunn diode exhibits multiple oscillations which were consistent with experimental observation due to non-uniformity of contact terminal. A downwards shift of oscillation frequency by varying the applied voltage across terminal was observed due to Gunn effect. The finding may be utilized not only to generate multiple millimeter wave or even terahertz signal sources on single chip, but also to achieve frequency tunability through tuning the applied bias voltage.