Preparation Methods of Graphene and Silicon Carbide

The preparation methods of graphene and silicon carbide (SiC) are mainly divided into two categories: mechanical methods and chemical methods.

Mechanical methods include micro the mechanical separation and the method of heating silicon carbide; Chemical methods include the chemical reduction method and the chemical cleavage method. Among them, the method of heating silicon carbide is to heat the single crystal 6h - SiC to remove Si, decomposing out of the graphene layer on the surface of the single crystal (0001).

The specific process is: Make the samples with oxygen or hydrogen etching processing under high vacuum heating by electron bombardment, to remove oxide. The oxide on the surface should be confirmed by auger electron spectroscopy that is completely removed, and then the sample should be heated to 1250 ~ 1450 ℃ after 1 min ~ 20 min, thus forming a graphite layer. After years of exploration, Berger and others have managed to produce single-layer or multilayer graphene. Its thickness is determined by the degree of heating, but it is quite difficult for the preparation of large area with a single thickness of graphene.

The method to heat SiC is a new way that commercialized SiC particles are viewed as raw materials by high cracking scale to prepare high quality free standing graphene materials. Based on the control of the raw material of silicon carbide particles and the cracking degree, the speed and atmosphere, it can realize the regulation of the structure and size of graphene. This is a very novel and important to achieve the practical application of graphene.

After decades of unremitting efforts, only a handful of universities and research institutions in the global have developed the silicon carbide crystal growth and processing technology at present. In terms of industrialization, only a few firms can provide silicon carbide wafer, and the domestic demand for silicon carbide wafer mostly depends on import. At present, silicon carbide wafer in the global market is quite expensive.

If the method of heating silicon carbide in China can achieve success and industrialization, the business of silicon carbide chip in the industries will usher in explosive growth.