Reduced 1/f noise in high-mobility BN-graphene-BN heterostructure transistors

Raman spectroscopy was used to determine the number of atomic planes in the exfoliated graphene samples and verify the quality of the selected flakes (see Figure 2 (a)). The optical microscopy images of the exfoliated BN and graphene flakes, and the resulting heterostructure are shown in Figure 2 (b-c). The current-voltage (I–V) characteristics of a representative BN-graphene-BN HFET are shown in Figure 3 (a). Both the effective and field-effect mobility extractions gave consistent results and the room-temperature (RT) mobility was determined to be ∼30,000 cm 2 /Vs at 7·10 11 cm −2 . The normalized 1/f noise spectral density of the graphene encapsulated device is presented in Figure 3 (b). We found that the channel-area normalized noise spectral density in BN-graphene-BN HFET is factor of ×5 – ×10 smaller than that in typical reference graphene FETs without channel encapsulation. The observed strong noise reduction can be related to screening of the traps in SiO 2 by the BN barrier. Other possible physical mechanisms and prospects of further noise suppression will be discussed at the presentation.