A Stochastic Large-Signal Model for Printed High-Frequency Rectifiers Used for Efficient Generation of Higher Harmonics

This article investigates the stochastic Schottky barrier variations of printed distributed Schottky diodes consisting of a self-assembled arrangement of crystalline silicon microcones onto a metal layer. The microcone formation emerges from an inkjet printed Si nanoparticle film after laser sintering, yielding a Schottky diode when a corresponding top metallization is applied. The $I - V$ characteristic and the voltage-dependent impedance of such diode is measured. By using the simulation software Advanced Design System (ADS), we develop a new scalable circuit model consisting of many different elementary diodes, which can explain the measured behavior. The elementary microcone diodes differ electrically in their barrier height, which is modeled as a stochastic process with a Gaussian distribution. A comparison between this model and a single diode model based on the thermionic field emission theory is conducted. We show that the distributed model outperforms the single-diode model in every regard and allows a prediction of the power levels of the harmonic frequency generation. Through more in-depth research, we find that a distributed barrier height leads to a smoother $I - V$ curve, which in turn can lead to higher second and third harmonic power levels. By adjusting the barrier height distribution, the desired harmonics can be increased.