Wigner function modeling of resonant tunneling diodes with high peak-to-valley ratios

Abstract

Wigner function simulations of structures with experimentally observed high peak-to-valley ratios are carried out. It is shown that if care is taken with the numerical method used, the simulations reproduce these sharp resonances. When scattering is ignored, peak-to-valley ratios of 33.7 are obtained for a pseudomorphic InGaAs-AlAs structure. The effects of phonon scattering are included to first order. Also, a small-signal analysis is carried out and the results are used to predict the rf power generation capability of these devices.

A Coupled Schrödinger Drift-Diffusion Model for Quantum Semiconductor Device Simulations

“…A related approach is based on the Pauli master equation (see, e.g., [21,28]) but requires negligible quantum correlations, which is sometimes questionable. Some authors simply use the semiclassical electron-phonon collision term in the Wigner equation [22,31], even though the Wigner function is not always positive. The full quantum treatment of electron-phonon interaction is very computationally demanding [26].…”

“…They require the self-consistent resolution of a quantum transport model with the Poisson equation. Much effort has been devoted to the Wigner equation (see the review in [22] and references therein, and also [27,31]). Simplified models make use of a semiclassical approximation of the charge density [33].…”

Device modeling in the Wigner picture

“…Dissipative interactions have been approached by means of phenomenological models based on the relaxation time approximation, [11][12][13] and also by introducing an actual Boltzmann-like collision operator [10,14]. The phonon collision operator acting upon the Wigner function has been initially suggested as an a priory assumption that 'is an adequate approximation at some level' [10].…”

Electronic Conductivity in Open Cylindrical Two-Barrier Symmetric Resonance Tunnel Structure

“…This equation can be solved within the approximation of small signal [5][6][7][8][9][10], assuming that the amplitude of the electric field ε is small. Thus, its general solution is written as:…”

“…One of the way of improving it, is to use the open RTS, where the life time of electron quasi-stationary states (QSS) is smaller than the duration of dissipative processes in the system. Such open RTS (mainly quasi-two-dimensional) are investigated for more than ten years using different theoretical models [5][6][7][8][9]. However, the consistent theory of their response is still far from the completion.…”