Conductive dendrite engineering of single-crystalline two-dimensional dielectric memristors

Public summary

* The variable single-vacancy density (nSV) is introduced during the growth of hexagonal boron nitride.

* The relationship between nSV and operating voltage was established experimentally, along with a corresponding model.

* The nSV determines the performance by regulating dendrites, as seen via scanning joule expansion microscopy.

* Memristors exhibit record performance with a set voltage of 26 mV and excellent power efficiency.

* Memristors with non-volatile and multi-resistive states are achieved with a retention time of over 10 years.

Abstract

Ultralow-power non-volatile memristors are key elements in electronics. Generally, power reduction of memristors compromises data retention, a challenge known as the “power-retention dilemma,” due to the stochastic formation of conductive dendrites in resistive-switching materials. Here, we report the results of conductive dendrite engineering in single-crystalline two-dimensional (2D) dielectrics in which directional control of filamentary distribution is possible. We find that the single-vacancy density (nSV) of single-crystalline hexagonal boron nitride (h-BN) plays an essential role in regulating conductive dendrite growth, supported by scanning joule expansion microscopy (SJEM). With optimized nSV, random dendrite growth is largely limited, and electrons hop between the neighboring Ag nanoclusters in vertical channels. The corresponding model was established to probe the relationship between nSV and memristor operating voltage. The conductive channel confinement in the vertical orientation contributes to long-retention non-volatile memristors with ultralow switch voltages (set: 26 mV; reset: −135 mV), excellent power efficiency (4 fW standby and a switching energy of 72 pJ) while keeping a high on/off resistance ratio of 108. Even at a record-low compliance current of 10 nA, memristors retains very robust non-volatile, multiple resistive states with an operating voltage less than 120 mV (the per-transition power low as 900 pW).