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Dr Yiwei Sun
BSc, PhD


Research Overview

Graphene, Nanomechnics, Environmental Effect, Raman Spectroscopy, DFT, High Pressure Techniques


My research is focused on the so-called “wonder material” graphene. Although graphene was predicted to revolutionise a wide range of electronic devices, such as transistors, this has not yet happened. I aim to understand and solve the major problems involved. For use in devices, monolayer graphene has to be supported on a substrate. The substrate not only dopes the graphene by the transfer of electrons, it also changes the mobility of the charge carriers in the graphene for reasons that are not well understood. I am undertaking a major study on optimising the substrate material and orientation for specific graphene devices. Another key problem is that as-grown graphene is n-doped but, surprisingly, after only a few hours in the atmosphere it becomes p-doped. I am investigating this, both experimentally and theoretically. This problem is related to the still unsolved question of why graphite is a solid-state lubricant on earth but not in space. My research has attracted considerable international interest and I have established collaborations with scientists in Spain, Austria, France and China. My research is exploited industrially through a strong collaboration with the UK graphene company, Paragraf, with whom I have regular meetings.