This presentation delivers about basics of [CNT] Carbon Nanotubes.

1. Carbon Nanotube [CNT]
By:
Arockiya nisha Arul Thomas
Department of Nanoscience And Technology.
Alagappa University, Karaikudi.

2. OUTLINE
 Introduction
 History
 Structure
 Synthesis
 Properties
 Application

3. What is CNT?
CNT is a tubular form of carbon with diameter as
small as 1nm.
Length: few nm to microns.
CNT is configurationally equivalent to a two
dimensional graphene sheet rolled into a tube.
Can have caps at the ends making them look like
pills

4. What CNT Really look like!
•Clumps, ropes, Bundles, mats
•Very high tendency to stick
together

5. History
In 1970s, Morinobu Endo prepared the first carbon
filament of nanometer dimensions
 Richard E. Smalley (Nobel Prize winning in 1996)
discovered the buckyball (C60) and other
fullerenes (1985)
 In 1991, Sumio Iijima had been using TEM
To analyze new type of finite carbon structure, that is
composed of needle-like tubes

6. Structure
 The structure of CNT can be
represented based on 2D
graphene lattice.
 Properties depending only
on tube diameter and chiral
angle.
 For a random chirality
distribution,1/3 of the
nanotubes are metallic

7. Types of CNTs
Single Wall CNT (SWCNT)
Consist of just one layer of carbon
average diameter 1.2 nm
Multiple Wall CNT (MWCNT)
Consist of 2 or more layers of carbon
average diameter 20 nm
(Can be metallic or
semiconducting depending on
their geometry)

8. Synthesis of CNT’s
Evaporation of solid carbon in arc discharge
Laser ablation
Catalytic chemical vapor deposition of carbon
containing gases

9. Arc Discharge
 Traditional method
 carried out in a medium of a Nobel Gas such as Helium or Argon.
 requires complex vacuum equipments.
 Such methods are, not only expensive but rather, time consuming too.
 only MWNT and ropes

10. Cont..
Two carbon electrodes are kept with a gap in
between. When high current, about 80 A is
passed through the electrodes where gap is
filled with helium under 300 torr. Cylindrical
deposit then grows at about 2 to 3 mm per
minute. This cathode deposit contains two
portions: the inside is a black fragile core and
the outside a hard shell.

11. Laser Abaltion
 A well mixed acetylene-air mixture is burned
inside a tube furnace
 A laser is used to vaporize a metal target (either
Fe or Ni)
 The post-flame exhaust gas is mixed with the
metallic vapor and allowed to cool
 During cooling, carbon nanotubes are formed
 Diameters, chiralities, metallic or
semiconductor all uncontrolled

12. Chemical vapor Depostion(CVD)
 Single SWNT for the 1st time.
 Aligned nanotubes
 Large scale possible
 Relatively cheap
 Diameters, chiralities, metallic or
semiconductor all uncontrolled

14. Properties
Electrical conductivity six orders of magnitude higher than copper
Can be metallic or semiconducting depending on chirality
- ‘tunable’ bandgap
- electronic properties can be tailored through application
of external magnetic field, application of mechanical deformation…
Very high current carrying capacity
Excellent field emitter; high aspect ratio
and small tip radius of curvature are
ideal for field emission

15. Application of CNT

16. Thank you