High Resolution Transmission Electron Microscope Study The Structure And Evolution Of Black Phosphorus And Carbon Nanotube Encapsulation

Transistor and integrated circuit are the cornerstone of modern information society.With the development of traditional silicon-based semiconductor technology approaching the physical limit,finding new channel materials and developing new semiconductor integrated circuit technology are the only way to break through the bottleneck of silicon-based technology.Low-dimensional materials with atomic thickness,such as two-dimensional materials(graphene,transition metal dichalcogenides,black phosphorus,etc.)and quasi one-dimensional materials(carbon nanotubes,graphene nanoribbon,etc.)have excellent physical properties and are expected to be the channel materials for the next generation of transistor technology.In this work,two-diemnsional black phosphorus and quasi-one-dimensional carbon nanotube encapsulation were selected to systematically study the structure,defects and properties of various materials.Structural defects,such as vacancies,adatoms,interstitial defects,dislocations,and grain boundaries,are inevitable in materials,and influence the material structure,properties,and performance.Due to confinement effects,their impacts are more profound for low-dimensional materials.In addition,the edge structure also plays an inevitable role in the chemical inertness and physical properties of two-dimensional or quasi one-dimensional materials.As an emerging two-dimensional material,black phosphorus is regarded as a promising material for high-performance nanoelectronic and optoelectronic devices.However,the current understanding of the structural defects and edge structures of black phosphorus mainly developed from theoretical calculations and was rarely confirmed experimentally,especially on the atomic scale.The inherent structural instability of black phosphorus under the conditions of water mixed oxygen atomosphere and electron beam irradiation,particularly for monolayers,is a major impediment.In this work,we successfully in situ construct mono-layer,bi-layer and multi-layer black phosphorus samples via combining the electron beam irradiation and in situ heating system,and further study the structural defects and edge configurations of black phsophorus.The decrease of size or dimensionality of two-dimensional material will introduce novel properties due to quantum confinement and edge effects.In this paper,we successfully synthesize the quasi one-dimensional materials(such as molybdenum disulfide nanotube,molybdenum disulfide nanoribbon,graphene nanoribbon and molybdenum telluride nanowire)and one-dimensional atomic chain(like phosphorus atomic chain and carbon atomic chain)based on the confinement effect of carbon nanotubes.The filled structures,physical properties and behaviors under high temperature heating of these encapsulated material were systematically study via high resolution transmission electron microscopy,nanodiffraction,Raman spectroscopy,X-ray diffraction,X-ray absorption near edge structure,and theoretical calculation.It was found that the filled structures and corresponding properties are highly dependent on the carbon nanotube diameter,for example,the filling phosphorus is a semiconducting linear single chain inside the carbon nanotube with a diameter of 8.0～10.0 ?,13.0～15.0 ? for half-metallic connected zigzag double chains,and 15.0～17.0 ? for semiconducting apart zigzag double chains.Constructing novel materaials with new structures and properties via filling the carbon nanotubes will expand the diversity of channel materials for the post-Moore era.