Structure and evolution of monolayer and multilayer chiral angle) CNT carbon nanotubes and CNTs (based on nano-microelectronics).

(Structure and evolution of monolayer and multilayer chiral angle) CNT carbon nanotubes and CNTs  (based on nano-microelectronics) Educational-Research Ph.D.

Researcher and author: PhD student :  Afshin Rashid

Note: layers of  nanotubes   can behave like a metal and electrically angles are done. Restructuring and building in them can  display semiconductor properties. Or is leading  , for example, minor changes can have on the winding tube from a metal to a semiconductor with a big gap.

Carbon nanotubes are hollow cylinders made of carbon atoms in a hexagonal structure. Two common structures of zigzag and armchair with multiple geometrical and behavioral characteristics are studied to evaluate the influence of structure type on mechanical properties changes, the most important of which is the modulus of elasticity. The two high-performance structures in the present study are modeled using finite element method in Mark's analysis software and the effect of changing the appearance of carbon nanotube structure on its modulus of elasticity has been studied. The behavior of covalent bonds between carbon atoms is also assumed by bending elements with a modulus of elasticity and a specified Poisson coefficient and applying a net tensile load to its upper surface to calculate the modulus of elasticity of the structures under study. Studies show that the armchair structure has a higher modulus of elasticity than the zigzag specimens.

Zigzag specimens always tend to increase their modulus of elasticity and reach the corresponding value corresponding to the ideal Armchair structure. The direction of rolling up (rolling or  chiral  vector) of the graphene layers determines the electrical properties of the nanotubes. Chirality describes the angle of the carbon nanotube hexagonal lattice. Not New pipes  seat  - so called because of the shape of the edge of their seats like - have the same chiral indices are full to guide them are much desired. They are not unlike  zigzag nanotubes   , which may be semiconductors. Converting a graphene sheet to 30 degrees, the nanotube changes from chair to chair to large or zigzag or vice versa.

While MWCNTs always achieve and achieve at least the same level of metal conductivity, the conductivity of SWCNTs depends on their chiral vector. The properties of carbon nanotubes are not similar.Currently, SWCNTs are prepared with various techniques such as arc discharge, hydrocarbon pyrolysis in the vicinity of the catalyst, laser evaporation and chemical vapor deposition. , Have springs and spirals. Various structures extend the properties and applications of SWCNTs, but newly synthesized SWCNTs contain many different nanotubes, the main obstacle to their use in high-efficiency nanotechnologies. The physical and electronic properties of a SWNT have been shown to depend on the diameter of the tube and its structure (m, n). In most applications, nanotubes with identical properties are required. Example: The performance of a CNT-based nanoelectronic device is dramatically improved by using identical nanotubes. Field effect transistors with off / on ratios of 106, using carbon nanotubes enriched (5,

Conclusion:

Changing structure and evolution and changing the monolayer and multilayer chiral angle CNT carbon nanotubes and CNTs are   widely used in energy storage, nanocomposites, nanoelectronics and nanosensors as a result (chiral angle shift and fracture) creating these properties Due to their large surface area, they are hollow structure, high mechanical strength, excellent electrical properties and unique electronic bonding structures. 

_{Author: Engineer Afshin Rashid} 

PhD student of Nano-Microelectronics at Islamic Azad University, Science and Research Branch, Tehran