Graphene enables clock rates in the terahertz range

                  Graphene is considered a promising candidate for the nanoelectronics of the future. In theory, it should allow clock rates up to a thousand times faster than today's silicon-based electronics. Scientists have now shown that graphene can actually convert electronic signals with frequencies in the gigahertz range extremely efficiently into signals with several times higher frequency.Today's silicon-based electronic components operate at clock rates of several hundred gigahertz (GHz), that is, they are switching several billion times per second. The electronics industry is currently trying to access the terahertz (THz) range, i.e., up to thousand times faster clock rates.

                A promising material and potential successor to silicon could be graphene, which has a high electrical conductivity and is compatible with all existing electronic technologies. In particular, theory has long predicted that graphene could be a very efficient "nonlinear" electronic material, i.e., a material that can very efficiently convert an applied oscillating electromagnetic field into fields with a much higher frequency. However, all experimental efforts to prove this effect in graphene over the past ten years have not been successful.

          The long-awaited experimental proof of extremely efficient terahertz high harmonics generation in graphene has succeeded with the help of a trick: The researchers used graphene that contains many free electrons, which come from the interaction of graphene with the substrate onto which it is deposited, as well as with the ambient air.