A hybrid quantum-classical model for transport in tunneling heterostructures

Several models have been developed to evaluate the current-voltage characteristics of the resonant tunneling diode (RTD). The current density predicted by both flat-band model and Thomas-Fermi approximation (or zero-current model) fails to reproduce the experimental results. We believe that this disagreement is due to the assumption of perfect electron coherence in the tunneling theory. An adjusted Thomas-Fermi model which includes a series resistance at either of the contact layers has been tried out, but the result is still unsatisfactory. A hybrid quantum-classical approach is suggested to evaluate self-consistently the electron current. The method couples the quantum-tunneling current obtained by solving the Schrodinger equation in the tunneling region with the classical drift-diffusion current in the contact layers. The resulting current continuity equation is solved self-consistently with Poisson's equation. It shows that the hybrid quantum-classical model gives much more realistic I(V) curves than other models.<
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