Physical vapor deposited 2D bismuth for CMOS technology

Two-dimensional(2D)bismuth,bismuthene,is an emerging pnictogen family member that has received increasing research attention in the past few years,which could yield exotic electrical,thermal,and optical properties due to unique band structure.This review provides a holistic view of recent research advances on 2D bismuth material synthesis and device applications in complementary metal oxide semiconductor(CMOS)technology.Firstly,the atomic and band structure of bismuthene is reviewed as the fundamental understanding of its physical properties.Then,it highlights material synthesis of 2D bismuth atomic sheets with emphasis on physical vapor deposition method with accurate layer controllability and process compatibility with CMOS technology.Moreover,it will survey latest applications of 2D bismuth in terms of electronic,optic,thermoelectric,spintronic and magnetic nanodevices.2D bismuth derivatives(Bi-X,X=Sb,Te,Se)will also be mentioned as a promising strategy to further improve device performance.At last,it concludes with a brief summary on the current challenges and future prospects in 2D bismuth and its derivatives for innovative electronics,sensors and other devices compatible with CMOS techniques.

Optically transparent graphene-based cognitive metasurface for adaptive frequency manipulation

Optically transparent microwave absorbing metasurfaces have shown great potential and are needed in multiple applications environments containing optical windows owing to their ability to reduce backscattering electromagnetic(EM)signals while keeping continuous optical observation.Meanwhile,they are also required to have adaptive EM manipulation capability to cope with complex and capricious EM environments.As a general approach,distributed circuit components,including positive-intrinsic-negative diodes and varactors and sensing components,are integrated with passive absorbing metasurfaces to realize adaptive control of microwave absorption.However,these circuit elements generally require bulky electrical wires and complex control circuits to regulate the operating state,resulting in the absorbing structures being optically opaque.Hence,it is a great challenge to realize self-operating absorbers while maintaining optical transparency.Here,we report an optically transparent cognitive metasurface made of patterned graphene sandwich structures and a radio frequency detector,which can achieve adaptive frequency manipulation to match incident EM waves.As a proof-of-principle application example,we realize a closed-loop automatic absorber system prototype of the proposed graphene metasurface with self-adaptive frequency variation,without any human intervention.The approach may facilitate other adaptive metadevices in microwave regime with high-level recognition and manipulation and,more generally,promote the development of intelligent stealth technologies.

Stretchable and self-healable spoof plasmonic meta-waveguide for wearable wireless communication system

Microwave transmission lines in wearable systems are easily damaged after frequent mechanical deformation,posing a severe threat to wireless communication.Here,we report a new strategy to achieve stretchable microwave transmission lines with superior reliability and durability by integrating a self-healable elastomer with serpentine-geometry plasmonic meta-waveguide to support the spoof surface plasmon polariton(SSPP).After mechanical damage,the self-healable elastomer can autonomously repair itself to maintain the electromagnetic performance and mechanical strength.Meanwhile,the specially designed SSPP structure exhibits excellent stability and damage resistance.Even if the self-healing process has not been completed or the eventual repair effect is not ideal,the spoof plasmonic meta-waveguide Can still maintain reliable performance.Self-healing material enhances strength and durability,while the SSPP improves stability and gives more tolerance to the self-healing process.Our design coordinates the structural design with material synthesis to maximize the advantages of the SSPP and self-healing material,signifcantly improving the relability and durability of stretchable microwave transmission lines.We also perform communication quality experiments to demonstrate the potential of the proposed meta-waveguide as interconnects in future body area network systems.