All-Metallic Vertical Transistors Based on Stacked Dirac Materials

Since the semiconductor industry based on Si is approaching limit of performance improvement, it is a persisting pursuit to use metal as channel material in a fi eld effect transistor (FET). All-metallic FETs could be scaled down to smaller size with less energy consume and performance at higher frequency. [ 1 ] No metal or semimetal has shown any notable fi eld effect until the appearance of graphene. [ 2 ] Graphene is semimetal but its current is sensitive to electrical fi eld due to its extreme thickness. However, the on/off current ratio of graphene is less than 30, and this greatly limits the application of pure graphene in electronics though its high carrier mobility of up to 10 5 cm 2 (V s) –1 is very attractive. [ 2 ]