Current saturation in zero-bandgap, top-gated graphene field-effect transistors

Graphene Field-Effect Transistors with Gigahertz-Frequency Power Gain on Flexible Substrates

“…This mobility is comparable to similar devices fabricated from exfoliated graphene on silicon substrates, 38,41 demonstrating the excellent electronic quality of the CVD graphene utilized in this work. Although mobility remains relatively constant with strain up to ε yy = 1.75%, the position of the Dirac point with respect to V gs is observed to shift with increasing strain.…”

“…We note, however, that the presence of residual resist residue from lithographic processing does not significantly contribute to the contact resistance between the graphene channel and evaporated electrodes, as the total contact resistance for this device is less than 300 Ω-μm, in the range best contact resistances reported for GFET devices (200-1,000 Ω-μm). [41][42][43] The ungated regions of the graphene channel will, however, effectively increase the contact resistance of the device. Improvements to the device architecture which act to minimize the gate-to-source and gate-to-drain spacer regions, such as by utilizing a self-aligned fabrication scheme, can further reduce the effective channel resistance.…”

High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals

“…Like in a long-channel transistor made of a covalent semiconductor, the saturation of current occurs in the MoS 2 TFT owing to pinch-off of the conducting channel at the drain side as the gate-drain diode becomes reverse-biased at high V DS . As graphene has zero bandgap, instead of pinch-off, the drain side of the conducting channel becomes p-type at high drain bias 9 , restricting current saturation and current modulation to a very small window, if at all. The bandgap of MoS 2 makes both current modulation and saturation robust, as borne out by Fig.…”

Role of Remote Interfacial Phonon (RIP) Scattering in Heat Transport Across Graphene/SiO2 Interfaces

“…[1][2][3] (We use surface polar phonons to refer to thermally excited vibrational modes near the surface that have an electric dipole moment, including e.g., surface phonon polaritons.) In RIP scattering, remote coupling between charge carriers in graphene or CNTs and SPPs in the polar substrates, spatially separated over a distance of <1 nm, is facilitated by oscillating surface electric fields created by the SPPs, and is accompanied by momentum and energy exchange.…”

“…In RIP scattering, remote coupling between charge carriers in graphene or CNTs and SPPs in the polar substrates, spatially separated over a distance of <1 nm, is facilitated by oscillating surface electric fields created by the SPPs, and is accompanied by momentum and energy exchange. 4 RIP scattering of charge carriers has been frequently invoked to explain electrical and optical properties of graphene and CNTs, e.g., the reduction of the mobility of charge carriers in supported graphene and CNTs, 1, 2 current saturation in graphene, 3,5 and nonvanishing absorption of light by graphene. 6 In principle, with the remote coupling through RIP scattering, remote energy transfer occurs between charge carriers in graphene (or CNTs) and the dielectric substrates.…”