Graphene quantum dots as a highly efficient solution-processed charge trapping medium for organic nano-floating gate memory

Abstract

A highly efficient solution-processible charge trapping medium is a prerequisite to developing high-performance organic nano-floating gate memory (NFGM) devices. Although several candidates for the charge trapping layer have been proposed for organic memory, a method for significantly increasing the density of stored charges in nanoscale layers remains a considerable challenge. Here, solution-processible graphene quantum dots (GQDs) were prepared by a modified thermal plasma jet method; the GQDs were mostly composed of carbon without any serious oxidation, which was confirmed by x-ray photoelectron spectroscopy. These GQDs have multiple energy levels because of their size distribution, and they can be effectively utilized as charge trapping media for organic NFGM applications. The NFGM device exhibited excellent reversible switching characteristics, with an on/off current ratio greater than 10(6), a stable retention time of 10(4) s and reliable cycling endurance over 100 cycles. In particular, we estimated that the GQDs layer trapped ∼7.2 × 10(12) cm(-2) charges per unit area, which is a much higher density than those of other solution-processible nanomaterials, suggesting that the GQDs layer holds promise as a highly efficient nanoscale charge trapping material.

Rapid synthesis and decoration of reduced graphene oxide with gold nanoparticles by thermostable peptides for memory device and photothermal applications

“…It is thought that the semi-metallic nature of rGO, having a covalently bonded honeycomb lattice structure, overcomes various defects including holes, which play an important role as charge trapping sites in charge trap memory devices. Transfer characteristics of ZnO TFT embedded with NAu-rGO nanocomposite exhibited a wider hysteresis window than that observed for various Au NP- and r-GO-based nano-floating gate dielectrics 55 , 56 . Figure 5e shows the output characteristics of the ZnO semiconductor layer with SiO 2 /NAu-rGO nanocomposite dielectric stack memory TFT as the gate voltage was varied from 0 to 40 V. The drain current increased with increasing gate voltage and reached saturation because of pinching-off of the active channel of the transistor, exhibiting typical n-type transistor behaviour.…”

Gate tunable giant anisotropic resistance in ultra-thin GaTe

“…In the following, we compare the GaTe FGM with the state-of-the-art memristors fabricated from other 2D materials. [21][22][23][24][25][26][27][28][29][30][31] Given that retention of the erased and/or programmed states is one of the most important parameter of such FGM, we recorded along direction-y the on state (by a positive gate pulse), and the off state (by a negative gate pulse), respectively. Among GaTe FGM devices tested, the best performance (measured from sample-S4 as shown in Fig.…”

High Performance Flexible Nonvolatile Memory Based on Vertical Organic Thin Film Transistor

“…Among the organic memory technologies, floating‐gate organic transistor memory (FGOTM) has attracted tremendous attentions due to its unique advantages, such as nondestructive read, sophisticated data‐storage mechanism, reliable long‐term data retention capacity, ultrahigh storage density, and easy compatibility with integrated circuits . Among the extensive research over the past decades, many efforts have been made on the study of structure of FGOTM and chargeable floating gate materials, including metal nanoparticles, semiconductor nanoparticles, small molecules, quantum dots, and carbon materials . Unfortunately, the key parameters such as driving ability and operating speed of FGOTM have received little attention, which are not only the important specification for applications in microelectronics such as organic electronics, integrated circuit, and sensors but also crucial for the fundamental understanding of the physical mechanism of carrier transport in FGOTM.…”