Figure 5: TI FET output characteristics.
From: Imperfect two-dimensional topological insulator field-effect transistors
(a) Output characteristics (Ids−Vds) of a TI FET for two different TIs, the first with Eg0=0.5 eV resulting in a bandgap of 0.33 eV and the second with Eg0=1.0 eV resulting in a bandgap of 0.5 eV. Accounting for the difference in the position of the valence maximum between both TIs, a gate bias of Vgs=−0.1 V is applied to the first and Vgs=0.V to the second. The imperfection scattering parameter is set to U=16 eV nm. At large drain bias in the on-state, negative differential resistance appears since scattering becomes inevitable. The peak at which the negative differential resistance occurs is proportional to the bandgap of the TI. (b) Similar to Fig. 4b for the larger bandgap 2D TI: Ids for Vds=0.3 V with U=16 eV nm on a linear scale with adjusted workfunctions. The nTI FET workfunction is decreased by 0.3 V and has Ioff,n=16 nA while the pTI FET workfunction is increased by 0.6 V and has Ioff,p=94 nA.
