Dual-Tunable Memristor Based on Carbon Nanotubes and Graphene Quantum Dots.

Lu Wang,Jing Yang,Yukai Zhang,Dianzhong Wen

doi:10.3390/nano11082043

Abstract

Nanocarbon materials have the advantages of biocompatibility, thermal stability and chemical stability and have shown excellent electrical properties in electronic devices. In this study, Al/MWCNT:GQD/ITO memristors with rewritable nonvolatile properties were prepared based on composites consisting of multiwalled carbon nanotubes (MWCNTs) and graphene quantum dots (GQDs). The switching current ratio of such a device can be tuned in two ways. Due to the ultraviolet light sensitivity of GQDs, when the dielectric material is illuminated by ultraviolet light, the charge capture ability of the GQDs decreases with an increasing duration of illumination, and the switching current ratio of the device also decreases with an increasing illumination duration (103–10). By exploiting the charge capture characteristics of GQDs, the trap capture level can be increased by increasing the content of GQDs in the dielectric layer. The switching current ratio of the device increases with increasing GQD content (10–103). The device can be programmed and erased more than 100 times; the programmable switching state can withstand 105 read pulses, and the retention time is more than 104 s. This memristor has a simple structure, low power consumption, and enormous application potential for data storage, artificial intelligence, image processing, artificial neural networks, and other applications.

Highlights

Graphene quantum dots were mixed into the carbon nanotube dispersion to prepare multiwalled carbon nanotubes (MWCNTs) with mass ratios of 1:0.125, 1:0.25, and 1:0.5, and ultrasonic oscillations were carried out for 1 h
The same voltage scanning method was used to test the other devices with different dielectric layer concentrations, and the results show that the Al/MWCNT/ITO device does not have resistance switching characteristics, while the graphene quantum dots (GQDs)-doped memristors all show bipolar resistance switching characteristics
Mass ratio of 1:0.5 are −1.23 V and 3.12 V, respectively, with corresponding standard deviations of 0.37 and 0.29. These results show that the threshold voltage distributions of the Al/MWCNT:GQD/ITO device with a MWCNT:GQD mass ratio of 1:0.5 are the most stable

Summary

Introduction

The materials used to fabricate memristors include perovskites [13], metal oxides [14], natural biomaterials [7,15,16], and organic dielectric materials [17]. Many memristors prepared with carbon nanotubes as a dielectric layer have been reported in the literature [18,19,20]. The electrical properties of corresponding memristors could be designed by controlling the parameters of the carbon nanotubes [21]. Thomas studied the electrical properties of a resistive switching device made of amorphous carbon, where the switching behavior was caused by a conductive pathway formed by transitions between the hybrid states of sp and sp3 [22]. The device had a switching current ratio of 103 –104 , a low threshold voltage and a resistance retention time of 3000 s [23]

Methods

Results

Conclusion