Suppression of 1/f noise in near-ballistic h-BN-graphene-h-BN heterostructure field-effect transistors

We have investigated low-frequency 1/f noise in the boron nitride–graphene–boron nitride heterostructure field-effect transistors on Si/SiO2 substrates (f is a frequency). The device channel was implemented with a single layer graphene encased between two layers of hexagonal boron nitride. The transistors had the charge carrier mobility in the range from ∼30 000 to ∼36 000 cm2/Vs at room temperature. It was established that the noise spectral density normalized to the channel area in such devices can be suppressed to ∼5 × 10−9 μm2 Hz−1, which is a factor of ×5 – ×10 lower than that in non-encapsulated graphene devices on Si/SiO2. The physical mechanism of noise suppression was attributed to screening of the charge carriers in the channel from traps in SiO2 gate dielectric and surface defects. The obtained results are important for the electronic and optoelectronic applications of graphene.