AA'-graphite is an
allotrope of carbon
Carbon is capable of forming many allotropy, allotropes (structurally different forms of the same element) due to its Valence (chemistry), valency. Well-known forms of carbon include diamond and graphite. In recent decades, many more allotrope ...
similar to
graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...
, but where the layers are positioned differently to each other as compared to the order in graphite.
AA’ stacking of
graphene
Graphene () is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. planes is another crystalline form of graphite (
orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...
, Fig. 1) which is
metastable
In chemistry and physics, metastability denotes an intermediate Energy level, energetic state within a dynamical system other than the system's ground state, state of least energy.
A ball resting in a hollow on a slope is a simple example of me ...
for Bernal AB graphite (
hexagonal
In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°.
Regular hexagon
A '' regular hexagon'' has ...
) (Fig. 2) and reveals a
nanocrystalline
A nanocrystalline (NC) material is a polycrystalline material with a crystallite size of only a few nanometers. These materials fill the gap between amorphous materials without any long range order and conventional coarse-grained materials. De ...
feature. Dr. Jae-Kap Lee discovered the new crystalline form of graphite in 2008
when he grew graphite onto diamond. He realized that graphene layers comprising graphite grew on
diamond
Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the Chemical stability, chemically stable form of car ...
(111) plane with stacked in the sequence of AA', due to the crystallographic feature of diamond.
The non-Bernal AA’ allotrope of graphite is synthesized by the thermal- and plasma-treatment of graphene nanopowders at ~1,500 °C. The formation of AA’
bilayer graphene
Bilayer graphene is a material consisting of two layers of graphene. One of the first reports of bilayer graphene was in the seminal 2004 '' Science (journal), Science'' paper by Geim and colleagues, in which they described devices "which containe ...
nuclei facilitates the preferred texture growth and results in single-crystal AA’ graphite in the form of
nanoribbon Nanoribbon may refer to:
* Graphene nanoribbons
* Silicene nanoribbons
* Boron nitride nanoribbons
* Gallium(III) oxide nanoribbons
* titanate nanoribbons - see titanium dioxide
* Phosphorene nanoribbons
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