Quantized current conduction in memristors and its physical model

Abstract

We report, for the first time, quantized conductance as a function of time in Au-CuS-Cu memristors under sub-threshold voltages. Non-integer quantum steps were modeled using multi-branch growth of nanowires at sub-threshold voltages. As each branch or fractional branch forms, the device conductance increases by an integral or fractional step correspondingly. In gated devices, the gate voltage (both +/- polarities) turned off devices eliminating the need for bipolar drain-source voltages. The gated memristors showed 106 On/Off current ratios with 10 mV/decade slope. The nanowires were also imaged using contact-mode AFM that clearly showed wires protruding out-of the devices plane. A computational model using Matlab was developed to qualitatively model the quantized conductance and gate field effects. Since nanowires can be dissolved/formed (i.e., programmed) electronically, their presence at the surface can be used to program the sensing mechanisms in these devices.