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MATERIALS SCIENCE & ENGINEERING . Part of . A Learner’s Guide. AN INTRODUCTORY E-BOOK. 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.
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MATERIALS SCIENCE & ENGINEERING Part of A Learner’s Guide AN INTRODUCTORY E-BOOK 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 http://home.iitk.ac.in/~anandh/E-book.htm Graphene
Graphene • Carbon is perhaps the most fascinating element in nature • The principal forms of carbon are: Graphite Diamond Fullerene, nanotubes and related structures • 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 forms the Graphene structure Not all carbon positions form a lattice
As atoms A & B do not have identical surrounding both cannot be lattice points
Structure of single graphene sheet Crystal = Lattice + Motif Grey atoms sit on the lattice positions Motif = 1 grey + 1 green (in positions as shown) • Either the green or the grey carbon atoms can be considered to be located at lattice points(but not both) • In plane motif consists of two C atoms • The unit cell is as marked