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

摘要

We have investigated low-frequency 1/f noise in the boron nitride-graphene-boron nitride heterostructure field-effect transistors on Si/SiO_2 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 cm~2/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) μm~2Hz~(-1), which is a factor of ×5-×10 lower than that in non-encapsulated graphene devices on Si/SiO_2. The physical mechanism of noise suppression was attributed to screening of the charge carriers in the channel from traps in SiO_2 gate dielectric and surface defects. The obtained results are important for the electronic and optoelectronic applications of graphene.