Electromagnetic Functions of Patterned 2D Materials for Micro–Nano Devices Covering GHz, THz, and Optical Frequency

Abstract

of 2D materials, understanding electromagnetic responses and exploiting abundant strategies to control electromagnetic wave are urgently needed for developing devices. [16][17][18] Patterned structures offer a platform to develop the potential of 2D materials deeply, and even break through some limits of traditional 2D materials. Geometric structures based on such crystals increase the freedom to manipulate electromagnetic wave, giving 2D materials infinite vitality. Recently, micro-nano devices integrated with patterned graphene, MXenes, MoS 2 , WS 2 , or black phosphorus are refreshing human being's cognition, pushing micro-nano devices into a new level. [19][20][21][22][23][24] However, there is still broad space for improvement. Designing a high-performance micro-nano device remains a great challenge. Selecting materials based on the intrinsic nature, arranging layout, tailoring patterned structures, choosing fabrication methods, as well as knowing physical mechanism of devices are all key links in designing a prominent device.Intellectualization, multifunction, automation, or high integration is an inevitable trend in various devices. Reasonable utilization of physical effects to improve performance, optimize figure of merit, and integrate multiple functionalities are becoming the theme of micro-nano devices. Herein, we start from the crystal and electronic structures of several typical 2D materials to summarize the available physical effects and electromagnetic response behaviors. We highlight the progress in preparing patterned 2D materials, and emphasize the mechanism of the micro-nano devices to broaden the horizons for designing devices. Finally, we predict future directions of fabrication techniques and point out the problems in current devices. Electronic Structures and Available Physical Effects of a 2D CrystalCrystal and electronic structures codetermine the properties of materials. Crystal structure, including constituent elements, 2D materials strongly drive the development of micro-nano devices, and patterned structures based on such crystals bring new opportunities. The advanced fabrication techniques of patterned 2D materials and the analysis of their electronic structures, and physical properties to provide access to diverse applications are discussed. Special attention is given to the hotspot electromagnetic functions and devices based on patterned 2D materials, including photodetectors, optoelectronic switches, modulators, polarization converters, gratings, as well as electromagnetic wave attenuation devices. Finally, a systematical outlook on the development of patterned 2D materials in micro-nano devices is presented, pointing out the current problems and exploring the most promising directions in the future. Patterned 2D Materials

A Nano-Micro Engineering Nanofiber for Electromagnetic Absorber, Green Shielding and Sensor

“…Many meritorious electromagnetic absorbing materials are emerging in recent decades, such as carbon materials, metal-based material, and polymers. [29][30][31][32]. Chen's group conducted a series of studies to explore microwave absorbing materials [33][34][35][36][37][38].…”

Printable Graphene–Insulator–Semiconductor (GIS) Heterostructures for Active Control of Infrared Q‐Switched Laser

“…[6] As a high mobility 2D material, graphene and its heterostructure can be operated as a widely cross-band Saturable (FET) devices. [26,27] Due to the high transparency derived from its plasma frequency in the infrared region, [29,30] the Si 3 N 4 insulator can both guarantee the laser penetration and suppress the operating current to obtain low modulating power. Additionally, the piezoelectric inkjet printing of silver ion ink provides an easy drop-on-demand and well-positioned method for the alignment and formation of silver contacts on GIS devices.…”

“…The peculiar GIS structure is built on a quartz substrate, where IGZO and nanomeshed graphene (N-gra) play crucial roles as extremely efficient semiconductor gating medium. [26][27][28] The Q-switched laser pulse is generated by the N-gra component of GIS device due to its nonlinear absorption characteristics. As an infrared-blind semiconductor, IGZO active layer can also exhibit extremely high on/off ratio for typical electron devices, such as metal-oxide-semiconductor (MOS) and field-effect-transistor 2D materials have recently attracted extensive attention in solid-state laser devices due to the improvement of their beam quality and service life.…”

Understanding of the Mechanism for Laser Ablation-Assisted Patterning of Graphene/ITO Double Layers: Role of Effective Thermal Energy Transfer

“…In the case of the wet etching process for the removal of the ITO layer, it is indeed challenging to maintain graphene-electrode patterns without damage. The electron-beam-lithography and plasma-etching techniques have been reported as some patterning methods for graphene [ 18 , 19 , 20 ]. On the other hand, such conventional lithography methods would be undesirable for patterning graphene/ITO because of their highly costly vacuum process.…”