What is a defect?

Defects are imperfections in the ideal arrangement of atoms in a crystal. The presence of a relatively small number of defects have a profound impact on the macroscopic properties of materials.
For example, When/if you buy a diamond ring, it is mostly the number and type of defects in the diamond crystal that define the amount of money you pay for a given crystal size.

There are 3 basic classes of defects in crystal:

  • Point defects - atoms missing or in irregular places in the lattice.
  • Linear defects - screw and edge dislocations.
  • Planar defects - the interfaces between homogeneous regions of the material.

    Defects in Graphene

    At nanoscale, defects could be extremely useful since they could be exploited to generate novel and innovative materials and devices. Graphene is no exception.
    When considering a perfect graphene lattice, every atom is coordinated to 3 other carbon atoms and every edge is shared by 2 faces.
    When Carbon atoms are removed, dangling bonds could be heald or make the structure more unstable and can be used to functionalize graphene with different atoms (doping).

    Effects of defects on Graphene

    Defects play a key role in graphene physicochemical properties.

    For Example, effect on electrical properties:


    Crystal Defects, University of Virginia
    The role of defects in 2D graphene sheets, IOP Science

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