HOPG: Highly Ordered Pyrolytic Graphite

HOPG is a very pure and highly ordered form of synthetic graphite which is characterised by its mosaic spread angle. HOPG is a laminar material and consists of layered polycrystals resembling a mosaic of mono crystal grains which are slightly disorientated with respect to each other. The size of individual crystals varies from 1-10um. A lower mosaic spread angle represents a better alignment of the graphite crystals and the best HOPG samples have a mosaic spread value of less than 1 degree.

The freshly cleaved HOPG substrates provides atomically flat areas which are used as a specimen substrate and for magnification calibration in scanning probe microscopy techniques (AFM, SPM, STM). Similar to mica, fresh HOPG surfaces can be made by cleaving. HOPG is made by annealing graphite under pressure at temperatures over 3000°C and this conductive material is stable up to 2000°C.°

Available in three qualities with 0.4, 0.8 and 3.5 degrees mosaic spread. The sample size is 10 x 10mm and thickness 1 or 2 mm. The samples are all double-sided which means that the full thickness can be used and they can be cleaved from both sides.

HOPG grade specifications and ordering information

Grade	ZYA	ZYB	ZYH
Product #	10-008311 / 10-008322	10-008333	10-008341 / 10-008342
Mosaic spread	0.4°	0.8°	3.5°
Accuracy	0.1°	0.2°	3.5°
Sides	Double
Thickness	1 or 2mm	1mm	1 or 2mm
Chip size	10 x 10mm
Application	SPM, STM, AFM, X-ray