https://www.technologyreview.com/s/409449/graphene-transisto... — uses narrow (< 10nm) bands of graphene produced by ultrasound.

https://phys.org/news/2016-05-graphene-based-transistor-cloc... — uses some tech I did not understand to put two sheets of graphene very close by and control the tunneling.

Both mention 2-3 orders of magnitude speedup, compared to silicon.