Highly oriented pyrolytic graphite is a semimetal in the bulk form and is a zero-gap semiconductor with metallic like properties when thinned down. Often times graphite also referred as semi-metallic since its conduction and valance bands overlap each other at different high symmetry points. 2Dsemiconductors USA have been working in the last 3 years to acquire expertise in carbonaceous materials such as graphite, graphene, diamond, and other polymeric material systems. Highly oriented pyrolytic graphite has been created by CVD enhanced pyrolysis technique. 2Dsemiconductors only provides highest quality HOPG crystals (in the literature it is often referred as ZYA grade). Instead of unknown terminalogies adopted, graphite, HOPG, and Kish graphite materials are characterized by a low mosaic spread angle. This angle correlates to how well individual graphite crystallites (single domains) are aligned with each other. The smaller the mosaic spread is the better alignment between single domains, easier exfoliation characteristics, and larger graphene sheets can be obtained. The best HOPG samples have mosaic spreads of less than 0.5 degree. Our crystals differ from other vendors in that our crystals consistently display only 0.3 degree mosaic spread.
Advantages of HOPG crystals from 2Dsemiconductors USA
- Designed, synthesized, and manufactured in USA. All the constituent precursors are all made in U.S.A and produced at our facilities.
- Each and every crystal is characterized one by one, many HOPG crystals with large mosaic spread are export to other companies.
- Defect density has been confirmed at 1E8 - 1E9 cm-2 density
- Our crystals exhibit predictable resistivity characteristics (see images)
- 100% compliance with USA customer protection act
Properties of HOPG crystals
Resistivity characteristics of HOPG crystals
STM surface characteristics of HOPG crystal (Park-AFM-STM systems)
Raman spectrum of HOPG from 2Dsemiconductors USA