Fig. 3: Capacitive coupling, intrinsic gain, and device performances.
From: Semiconductor-less vertical transistor with ION/IOFF of 106
Capacitive coupling of a GFET and b FEB. c Work function shift by varying the Ctotal = CTC + CGate. Ctotal = 6.9 μF/cm2 when tGate = 1 nm and tTC = 1 nm; Ctotal = 0.69 μF/cm2 when tGate = 10 nm and tTC = 10 nm; and Ctotal = 0.069 μF/cm2 when tGate = 100 nm and tTC = 100 nm. The work function modulation of GFET is the upper limit of that of the FEB. d Intrinsic gain (gm/gds) by varying the tTC/tGate. The intrinsic gain is proportional to the tTC/tGate (the red dotted line is for guidance). e Device performances when tTC is 19.5, 30.7, 32, 49, 50, and 54.8 nm, and tGate is 27.8, 42.8, 33, 36, 52, and 54.4 nm, respectively. ION, 1/τ, fT, and PDP increase with tTC. They increase to ~1000 times as tTC increases by ~35 nm, except for PDP. f Field-emission barrier height by varying tTC, extracted by single-emitter approximation. The barrier height between graphene’s Dirac point and the conduction band decreases as tTC increases. It decreases by 1.2 eV, as tTC increases from 19.5 to 301 nm. g Temperature-dependent performances of FEB. ION of the most FEBs (e.g., device 1, black shapes) varies only 11.5% as temperature increases from 1.78 to 300 K; τ does <2.1%; fT does 10.6%; PDP does 1.5%. In contrast, some devices such as 2 (red shapes) exhibited temperature-dependent performances: ION varies 314%; τ does 17.9%; fT does 177%; PDP does 17.9%.
