Which one of the following is not a property of 'graphene' ?

Graphene is a single atomic layer of carbon atoms arranged in a hexagonal lattice, making it the thinnest material known to science with a thickness of approximately 0.334 nm. It possesses exceptional optical transparency, absorbing only about 2.3% of white light, which makes it almost completely transparent to the human eye. Furthermore, it is highly conducting due to its unique electronic structure where delocalized pi bonds allow for fast charge carrier mobility, significantly exceeding that of silicon [1]. However, graphene is naturally a zero band-gap semiconductor (or semi-metal) because its valence and conduction bands touch at the Dirac points [1]. This lack of a band gap is a primary challenge in using it for traditional transistors, as it cannot be easily switched 'off'. Therefore, the claim that it is a wide band-gap semiconductor is incorrect.

Sources

1. [1] https://www.sciencedirect.com/topics/chemical-engineering/graphene