Effect of front and back gates on beta-Ga2O3 nano-belt field-effect transistors

Abstract

Field effect transistors (FETs) using SiO2 and Al2O3 as the gate oxides for the back and front sides, respectively, were fabricated on exfoliated two-dimensional (2D) beta-Ga2O3 nano-belts transferred to a SiO2/Si substrate. The mechanical exfoliation and transfer process produced nano-belts with smooth surface morphologies and a uniform low defect density interface with the SiO2/Si substrate. The depletion mode nanobelt transistors exhibited better channel modulation with both front and back gates operational compared to either front or back-gating alone. The maximum transconductance was similar to 4.4 mS mm(-1) with front and back-gating and similar to 3.7 mS mm(-1) with front-gating only and a maximum drain source current density of 60 mA mm(-1) was achieved at a drain-source voltage of 10 V. The FETs had on/off ratios of similar to 10(5) at 25 degrees C with gate-source current densities of similar to 2 x 10(-3) mA mm(-1) at a gate voltage of -30 V. The device characteristics were stable over more than a month for storage in air ambient and the results show the potential of 2D beta-Ga2O3 for power nanoelectronics. Published by AIP Publishing.