Emitter Spacer Layers Influence on the Dynamic Characteristics of Resonant-Tunneling Diode

Within the framework of the coherent quantum-mechanical model, which is based on the solution of the time-dependent Schrödinger equation with exact open boundary conditions, we have numerically analyzed the behavior of the InGaAs/AlAs resonant-tunneling diode (RTD) in an alternating-current electric field in the presence of spacer layers. It is shown that the interaction of the energy levels in a quantum well of the RTD, and the same in a quantum well of the emitter spacer, leads to splitting of these levels, which sharply increases the active current of RTD. In this case, the value of the active current at the finite frequencies may exceed the active current within the low-frequency limits. For RTD, heterostructure considered active current at frequency 1.77 THz takes its maximum value at the thickness of the emitter spacer equals to 6.5 nm exceeding the corresponding value in the absence of the spacer by the factor of 32. The results obtained in this paper may be useful to improve the frequency characteristics of resonant-tunneling nanostructures.