Abstract
We reported a graphene field-effect transistor (GFET) based on CVD
Ge-based graphene and primarily investigated the low-temperature
electrical characteristics. The self-alignment technique was used to
fabricate GFET to reduce parasitic effects and improve transconductance
and cut-off frequency. To further explore the electrical properties, we
studied the direct current and radio frequency characteristics of the
GFET over a temperature range from 4.2 K to 300 K, considering the
temperature-dependent resistivity of intrinsic Ge. The DC characteristic
of the GFET for 110 nm gate length, particularly the transconductance
performance, exhibits a tiny variation of only ~ 5%
across this temperature range. However, the cut-off frequency
experiences a considerable increase, improving several tens of times
when the temperature decreases to 4.2 K, with a maximum value of 3.49
GHz. This work illustrates a meaningful advancement in applying GFETs in
the lowtemperature, high-frequency domain.