handout11 - 1 ECE 407 Spring 2009 Farhan Rana Cornell...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 ECE 407 Spring 2009 Farhan Rana Cornell University Handout 11 Energy Bands in Graphene: Tight Binding and the Nearly Free Electron Approach In this lecture you will learn: The tight binding method (contd) The -bands in graphene FBZ Energy ECE 407 Spring 2009 Farhan Rana Cornell University Graphene and Carbon Nanotubes: Basics a 3 a a x y 1 a v 2 a v a y x a + = 2 1 2 3 1 v a y x a = 2 1 2 3 2 v A B Graphene is a two dimensional single atomic layer of carbon atoms arranged in a Honeycomb lattice (which is not a Bravais lattice) The underlying Bravais lattice is shown by the location of the black dots and is a hexagonal lattice There are two carbon atoms per primitive cell, A and B (shown in blue and red colors, respectively) Graphene can be rolled into tubes that are called carbon nanotubes (CNTs) CNT CNT a = 2.46 A 2 ECE 407 Spring 2009 Farhan Rana Cornell University Graphene: Sp2 Hybridization All carbon atoms are all sp2 hybridized (one 2s orbital together with the 2p x and the 2p y orbitals generate three sp2 orbitals) All sp2 orbitals form -bonds with the sp2 orbitals of the neigboring carbon atoms The bonding orbital associated with each -bond is occupied by two electrons (spin-up and spin-down) There is one electron per carbon atom left in the 2p z orbital x y Sp2 hybridization in carbon: ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) r r r r r r r r r r r...
View Full Document

Page1 / 6

handout11 - 1 ECE 407 Spring 2009 Farhan Rana Cornell...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online