Theoretical investigation of negative differential conductance regime of silicon nanocrystal single-electron devices

The current-voltage characteristics of metal-insulator-Si quantum dot (QD)-insulator-metal structures are numerically simulated to investigate the design and the possible applications of single-electron devices taking advantage of Coulomb-blockade phenomenon. The simulation technique is based on a physical description of the devices and only requires fundamental quantities of the system but no fitting parameter. One of the originality of this work lies in the accurate calculation of tunneling rates by a perturbation method, which allows us to properly include the effect of a bias voltage on the wave functions in the QD. As a consequence, we show that the bias influence on the wave function may lead to negative-differential-conductance effects depending on the design of the structure.