Intrinsic High‐frequency Oscillations and Equivalent Circuit Model in the Negative Differential Resistance Region of Resonant Tunneling Devices

Intrinsic high‐frequency oscillations (≈2.5 THz) in current and corresponding quantum well density, which have been simulated for a fixed bias voltage in the Negative Differential Resistance (NDR) region of the Current‐Voltage (I‐V) characteristics of a Resonant Tunneling Diode (RTD), suggest an equivalent nonlinear autonomous circuit model. The intrinsic circuit parameters are calculated directly from the results of the quantum transport numerical simulations. These consist of a resistor in series with a two‐branch parallel circuit, one branch consists of a capacitor and the other branch consists of an inductor in series with a nonlinear resistor. It is however suggested that much more complex external circuit‐induced behavior can occur in real RTD experiments.