A NOTE ON CURRENT-VOLTAGE CHARACTERISTICS FROM THE QUANTUM HYDRODYNAMIC EQUATIONS FOR SEMICONDUCTORS

The quantum hydrodynamic model is primary used for the simulation of r esonant tunneling diodes. The current-voltage characteristics of these diodes show negative differential resistance (NDR) effects. For two s implified one-dimensional quantum models derived by means of asymptoti c analysis, explicit formulas of the current-voltage characteristics a re given. It turns out that not only the quantum correction term but a lso the convection term are mathematically responsible for the NDR eff ects. This observation is confirmed by numerical simulations of the fu ll isothermal quantum hydrodynamic model.