3 research outputs found
Wafer-scale graphene/ferroelectric hybrid devices for low-voltage electronics
Preparing graphene and its derivatives on functional substrates may open
enormous opportunities for exploring the intrinsic electronic properties and
new functionalities of graphene. However, efforts in replacing SiO have
been greatly hampered by a very low sample yield of the exfoliation and related
transferring methods. Here, we report a new route in exploring new graphene
physics and functionalities by transferring large-scale chemical vapor
deposition single-layer and bilayer graphene to functional substrates. Using
ferroelectric Pb(ZrTi)O (PZT), we demonstrate ultra-low
voltage operation of graphene field effect transistors within V with
maximum doping exceeding and on-off ratios larger
than 10 times. After polarizing PZT, switching of graphene field effect
transistors are characterized by pronounced resistance hysteresis, suitable for
ultra-fast non-volatile electronics.Comment: 4 pages, 3 figures; EPL 2011; In pres
Quasi-Periodic Nanoripples in Graphene Grown by Chemical Vapor Deposition and Its Impact on Charge Transport
The technical breakthrough in synthesizing graphene by chemical vapor deposition methods (CVD) has opened up enormous opportunities for large-scale device applications. To improve the electrical properties of CVD graphene grown on copper (Cu-CVD graphene), recent efforts have focused on increasing the grain size of such polycrystalline graphene films to 100 μm and larger. While an increase in grain size and, hence, a decrease of grain boundary density is expected to greatly enhance the device performance, here we show that the charge mobility and sheet resistance of Cu-CVD graphene is already limited within a single grain. We find that the current high-temperature growth and wet transfer methods of CVD graphene result in quasi-periodic nanoripple arrays (NRAs). Electron-flexural phonon scattering in such partially suspended graphene devices introduces anisotropic charge transport and sets limits to both the highest possible charge mobility and lowest possible sheet resistance values. Our findings provide guidance for further improving the CVD graphene growth and transfer process