Ge‐based graphene FET for low‐temperature electronics

Abstract

Abstract A graphene field‐effect transistor (GFET) based on chemical vapour deposited (CVD) Ge‐based graphene was reported and the low‐temperature electrical characteristics primarily investigated. The self‐alignment technique was used to fabricate a GFET to reduce parasitic effects and improve transconductance and cut‐off frequency. To further explore the electrical properties, the direct current and radio frequency characteristics of the GFET were studied over a temperature range from 4.2 to 300 K, considering the temperature‐dependent resistivity of intrinsic Ge. The direct current 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 low‐temperature, high‐frequency domain.

Keywords

• cryogenic electronics
• graphene
• graphene devices
• nanofabrication
• radiofrequency measurement