GrapheneGraphene
MATERIALS SCIENCEMATERIALS SCIENCE
&&
ENGINEERINGENGINEERING
Anandh Subramaniam & Kantesh Balani
Materials Science and Engineering (MSE)
Indian Institute of Technology, Kanpur- 208016
Email: anandh@iitk.ac.in, URL: home.iitk.ac.in/~anandh
AN INTRODUCTORY E-BOOKAN INTRODUCTORY E-BOOK
Part of
A Learner’s GuideA Learner’s Guide
A Learner’s GuideA Learner’s Guide
Carbon is perhaps the most fascinating element in nature
The principal forms of carbon are: Graphite Diamond Fullerene, nanotubes and related structures
Graphene
A single sheet of graphite is called graphene
It is sp2 hybridized covalently bonded
The bonding between the graphene sheets in graphite is of van der Walls type
In this set of slides we consider crystallographic concepts related to graphene
It is a hexagonal array of Carbon atoms, which is NOT a lattice
Part of the hexagonal array of C atoms which formsthe Graphene structure
Not all carbon positionsform a lattice
As atoms A & B do nothave identical surroundingboth cannot be latticepoints
Crystal = Lattice + Motif
Grey atoms sit on thelattice positions
Motif = 1 grey + 1 green
(in positions as shown)
Structure of single graphene sheet
Either the green or the grey carbon atoms canbe considered to be located at lattice points(but not both)
In plane motif consists of two C atoms
The unit cell is as marked
