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The reverse‐biased current of a Schottky junction comprises the thermionic emission current and the Fowler–Nordheim tunneling current, depending on the barrier height and thickness. Because both are fixed at traditional Schottky junctions, so is the current mechanism. However, a barristor junction has a tunable barrier height and the current mechanism changes accordingly. Here, the evolution of the current mechanism of the graphene–WS2 junction is investigated by varying the gate voltage, drain voltage, and temperature. As the height decreases with the accumulation of electrons on graphene, the dominant transport mechanism of the junction changes from thermionic to field emission. As the temperature increases, the extrinsic carrier concentration of WS2 increases and thus the thickness decreases, resulting in the same evolution. In addition, a kink in the ID–VD curves over a specific range of gate voltages and temperatures is observed. This may originate from the alignment of the Fermi level of graphene to the Dirac point, which dramatically reduces the Fowler–Nordheim tunneling current. [ABSTRACT FROM AUTHOR]

We investigated the tunneling of graphene/insulator/metal heterojunctions by revising the Tsu–Esaki model of Fowler–Nordheim tunneling and direct tunneling current. Notably, the revised equations for both tunneling currents are proportional to V3, which originates from the linear dispersion of graphene. We developed a simulation tool by adopting revised tunneling equations using MATLAB. Thereafter, we optimized the device performance of the field-emission barristor by engineering the barrier height and thickness to improve the delay time, cut-off frequency, and power-delay product. [ABSTRACT FROM AUTHOR]