Current saturation in zero-bandgap, top-gated graphene field-effect transistors.
The novel electronic properties of graphene, including a linear energy dispersion relation and purely two-dimensional structure, have led to intense research into possible applications of this material in nanoscale devices. Here we report the first observation of saturating transistor characteristics in a graphene field-effect transistor. The saturation velocity depends on the charge-carrier concentration and we attribute this to scattering by interfacial phonons in the SiO2 layer supporting the graphene channels. Unusual features in the current-voltage characteristic are explained by a field-effect model and diffusive carrier transport in the presence of a singular point in the density of states. The electrostatic modulation of the channel through an efficiently coupled top gate yields transconductances as high as 150 microS microm-1 despite low on-off current ratios. These results demonstrate the feasibility of two-dimensional graphene devices for analogue and radio-frequency circuit applications without the need for bandgap engineering.
Meric
Inanc
I
Department of Electrical Engineering, Columbia University, New York 10027, USA.
Han
Melinda Y
MY
Young
Andrea F
AF
Ozyilmaz
Barbaros
B
Kim
Philip
P
Shepard
Kenneth L
KL
D002244:Carbon / Q000737:chemistry; D025802:Electric Capacitance; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D014173:Transistors, Electronic
D011084:Polycyclic Aromatic Hydrocarbons; D002244:Carbon