· Researchers at Delhi’s National Physical Laboratory (CSIR-NPL) have designed a low-pressure chemical vapour deposition (LPCVD) device that allows high quality, single-layer graphene to be grown.
· The quality of the single-layer graphene is metrology-grade, and can be used in next-generation quantum devices.
· About one billion grains are highly connected to give a single continuous layer of graphene.
· The LPCVD device developed indigenously costs about Rs.5,00,000, which is one-tenth of the imported ones.
· More importantly, the quality of the single-layer graphene grown using this device is superior than the ones reported in the literature.
· When attempts are made to grow larger graphene single layers, it is difficult to control the diffusion of carbon atoms which get deposited on the copper substrate. This compromises the quality of graphene single layer produced.
· Generally, LPCVD devices have three mass flow meters through which hydrogen, argon and hydrocarbon gases are supplied to grow the graphene.
· Since the mass flow meters are expensive, two such meters that supply argon and hydrocarbon are replaced with calibrated rotameters as it is easy to control the flow of these gases due to higher molecular weight.
· The graphene was grown on a substrate made of copper, which acts as a catalyst.
Source : The Hindu
10.03.2019