Transient switching behavior of the resonant-tunneling diode

A quantum mechanical analysis is used to treat the transient behavior of the resonant-tunneling diode (RTD). The use of the Wigner formalism permits inclusion of the quantum mechanics inherent in the device, while offering a Boltzmann-like equation that is rather easily implemented. Self-consistent treatment of the potential introduces plasma oscillations in the distribution, which leads to the oscillatory current transient. Fourier analysis of this transient indicates that the RTD behaves inductively at frequencies under 2 THz, consistent with the ballistic nature of the carriers. At higher frequencies, the dominant mechanism is the capacitive charging and discharging of the quantum well, which leads to capacitive behavior of the device. The real part of the conductance is negative for frequencies under 1.5 THz, and positive for higher frequencies. The critical frequencies are shown to be independent of the relaxation time used to model dissipation, although the magnitude of the conductance decreases as the dissipation increases.<
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