Highly Ordered Pyrolytic Graphite

Follow NanoScanTech on Twitter

 

Highly Ordered Pyrolytic Graphite. AFM image. Contact mode. Image size 9,3x10,3 μм. 300x300 points. Image was obtained with  SPM Certus Standard.


HOPG. AFM image.  Contact mode. Topography.

Highly oriented (ordered) pyrolytic graphite, HOPG - a form of graphite.

Graphite is one of the allotropes of carbon. It has a layered structure. Each layer consists of carbon atoms packed in a hexagonal lattice. The distance between arranged carbon atoms is 0.142 nm. The distance between the layers of graphite is 0.335 nm. Separate layers of graphite are parallel to each other and are connected by Van der Waals forces to form crystallites (crystal grains). Generally, in graphite single crystals are not ordered.

In some cases, the individual crystallites are ordered, so all the layers of graphite are almost parallel to each other. Such a graphite is both natural and artificial. Artificial called highly oriented pyrolytic graphite or HOPG.

For scanning probe microscopy HOPG is interesting for several reasons:

  • HOPG is a "natural" standard for scanning probe microscopy. Because it is known the distance between the individual layers, you can calibrate the SPM c using the obtained images of the surface of graphite;
  • When using scanning tunneling microscope to visualize individual atoms in the graphite lattice and subsequently calibrate STM.
  • HOPG has an atomically smooth surface, making it a good material for the samples substrate.

 

 

Ванадиевая тестовая    решетка NSpec (конфокальное лазерное изображение)

Test samples Gallery                    
Polystyrene spheres 

Полистирольные сферы