Proposal of a semiconductor klystron device for THz range using two-dimensional electron gas

An amplifier device with two-dimensional electron gas, which has a possibility of operating in the THz range, was proposed and analyzed. In the operation principle, electrons traversing the input port emit and absorb THz photons, resulting in the splitting of the electron energy levels, and then, the beat of these splitting electron waves produces charge density modulation which emits an amplified output power at the output port. This operation principle is equivalent to that of the klystron tube in the low-frequency classical limit. Transconductance and power gain are analyzed quantum mechanically including the influence of electron scattering and electron energy distribution. Calculated results show that the transconductance has a peak in the sub-THz and THz ranges. An oscillator using this device integrated with a coplanar line and a slot antenna is proposed, and the possibility of THz oscillation is shown by the analysis of oscillation conditions.