Terahertz spectroscopy helps maintain purity of graphene

Because it’s so easy to accidently introduce impurities into graphene, labs led by physicists Junichiro Kono of Rice and Masayoshi Tonouchi of Osaka’s Institute of Laser Engineering discovered a way to detect and identify out-of-place molecules on its surface through terahertz spectroscopy.

They expect the finding to be important to manufacturers considering the use of graphene in electronic devices.

’For any future device designs using graphene, we have to take into account the influence of the surroundings’

The research, published in Scientific Reports, was made possible by the Rice-based NanoJapan program, through which American undergraduates conduct summer research internships in Japanese labs.

A single molecule of a foreign substance can contaminate graphene enough to affect its electrical and optical properties, Kono said. According to Rice, this includes electrical contacts.

‘Traditionally, in order to measure conductivity in a material, one has to attach contacts and then do electrical measurements,’ Kono said in a statement. ‘But our method is contact-less.’