Integration of Nanoscale and Macroscale Graphene Heterostructures for Flexible and Multilevel Nonvolatile Photoelectronic Memory

Abstract

The development of optical memory with attractive features such as long-lasting, nonvolatile, high-speed, and low-energy consumption is vitally important in the information age. Owing to these advantages, optical memory has been popular for more 10 years. Recently, flexibility has become desirable for the application of wearable devices and smart artificial intelligence; for conventional optical memory, this is still difficult to achieve. To combine optical memory with soft materials, this study presents a flexible and photoelectronic switchable multilevel memory device with long-lasting nonvolatile properties. On the basis of the integration of nanoscale (graphene nanoflakes) and macroscale graphene heterojunctions, a device achieves switchable memory states up to 196 distinct levels under the illumination of lasers with different wavelengths. The photoelectronic memory device can be written optically and erased by both optical and electric methods. Additionally, the device possesses several unique features including a low working bias of 0.5 V, nonvolatility for over 10 000 s, and mechanical stability for more than 10 000 bending cycles. Notably, in previous studies, polymers with poor mobility were used as a conducting channel, which can greatly limit the amplitude of the light-induced switching ratio and electrical performance. In stark contrast, in our device, the graphene layer with the mobility exceeding several orders of magnitude was used to serve as a conducting channel, enabling one to overcome the existing shortcoming. Our approach therefore not only provides an alternative paradigm for the development of photoelectronic memory but also holds great promise for practical applications due to its compatibility with current technologies.

A Review on the Production Methods and Applications of Graphene-Based Materials

“…In addition, these can be incorporated into textiles in various forms with excellent washability compared to the previously used solid-state gas sensors [ 241 ]. Furthermore, as different gases, volatile organic compounds (VOCs), and humidity can be detected with GO-based gas sensors, these sensors are found to be responsive for detecting any environmental change including the identification of different hazardous materials such as toxic gases, organic vapours, and chemical warfare agents [ 237 , 242 ]. Thus, graphene/polymer composites facilitate keeping the environment safe from various harmful materials [ 242 , 243 ].…”

“…Furthermore, as different gases, volatile organic compounds (VOCs), and humidity can be detected with GO-based gas sensors, these sensors are found to be responsive for detecting any environmental change including the identification of different hazardous materials such as toxic gases, organic vapours, and chemical warfare agents [ 237 , 242 ]. Thus, graphene/polymer composites facilitate keeping the environment safe from various harmful materials [ 242 , 243 ]. Apart from this, human body temperature, blood pressure, and heartbeat can be easily measured with the help of these sensors used as wearable devices.…”

Strain Engineering in 2D Material‐Based Flexible Optoelectronics

“…2D materials have a set of excellent mechanical properties, which can be integrated into the high‐density device arrays to obtain greater space adaptability. Flexible 2D optoelectric devices have a huge potential in complex imaging, [ 97 ] neural computation, [ 98 ] nonvolatile photoelectronic memory, [ 99 ] emitter, [ 100 ] and light emitter devices (LEDs). [ 101 ] In this section, we mainly focus on the recent developments of 2D material‐based flexible optoelectronic integrations, such as image sensors, artificial synapses, and LEDs, especially in the context of device design, new materials, and performance analysis.…”

Realizing Nonvolatile Photomemories with Multilevel Memory Behaviors Using Water-Processable Polymer Dots-Based Hybrid Floating Gates

“…Due to the booming growth of cloud computing and big data, the conventional storage devices are no longer sufficient to satisfy the demand of high memory characteristics. To this end, the recent research focus on memory devices has been diverted from electrical programming into optical programming, which can greatly raise the efficiency in data transfer and energy saving. − Among the plethora of apparatus for optical communications, photomemory has surged significant research interest and been considered as the next-generation storage device. Given the collective advantages of light, such as ultrafast signal transmission, wide bandwidth, and electrically/optically orthogonal operability, photomemory possesses not only the noncontact programming advantage with a simplified device structure but also fast response time that can be down to 1 ns, providing prospective future in the fields of light information storage, image sensing, encrypted storage, light computing, and wearable sensorimotor applications. − …”