A high-performance low-voltage graphene field-effect transistor (FET) array was fabricated on a flexible polymer substrate using solution-processable, high-capacitance ion gel gate dielectrics. The high capacitance of the ion gel, which originated from the formation of an electric double layer under the application of a gate voltage, yielded a high on-current and low voltage operation below 3 V. The graphene FETs fabricated on the plastic substrates showed a hole and electron mobility of 203 ( 57 and 91 ( 50 cm2 /(V·s), respectively, at a drain bias of -1 V. Moreover, ion gel gated graphene FETs on the plastic substrates exhibited remarkably good mechanical flexibility.
We developed means to produce wafer scale, high-quality graphene films as large as 3 in. wafer size on Ni and Cu films under ambient pressure and transfer them onto arbitrary substrates through instantaneous etching of metal layers. We also demonstrated the applications of the large-area graphene films for the batch fabrication of field-effect transistor (FET) arrays and stretchable strain gauges showing extraordinary performances.
The outstanding electrical1 , mechanical2,3 and chemical4,5 properties of graphene make it attractive for applications in flexible electronics6?8. However, efforts to make transparent conducting films from graphene have been hampered by the lack of effi- cient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications.
This paper reports a mechanically flexible, transparent thin film transistor that uses graphene as a conducting electrode and single-walled carbon nanotubes (SWNTs) as a semiconducting channel. These SWNTs and graphene films were printed on flexible plastic substrates using a printing method. The resulting devices exhibited a mobility of ∼2 cm2 V?1 s?1, On/Off ratio of ∼102, transmittance of ∼81% and excellent mechanical bendability.
We report substantially enhanced photoluminescence (PL) from hybrid structures of graphene/ZnO films at a band gap energy of ZnO ( 3:3 eV=376 nm). Despite the well-known constant optical conductivity of graphene in the visible-frequency regime, its abnormally strong absorption in the violet-frequency region has recently been reported. In this Letter, we demonstrate that the resonant excitation of graphene plasmon is responsible for such absorption and eventually contributes to enhanced photoemission from structures of graphene/ZnO films when the corrugation of the ZnO surface modulates photons emitted from ZnO to fulfill the dispersion relation of graphene plasmon.
This work demonstrates a large-scale batch fabrication of GaN light-emitting diodes (LEDs) with patterned multi-layer graphene (MLG) as transparent conducting electrodes. MLG films were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized MLG film properties, possessing a sheet resistance of ∼620 / with a transparency of more than 85% in the 400?800 nm wavelength range. T
Raman spectra of a single layer graphene sheet placed in different gold substrates were obtained and are discussed in the context of surface enhanced Raman scattering (SERS). The gold substrates were composed of a combination of a thermally deposited gold film and a close-packed gold nanosphere layer. The SERS effects were negligible when the excitation wavelength was 514 nm, while the Raman signals were enhanced 3- to 50-fold when the excitation wavelength was 633 nm.
Since the discovery of microscale single-layer graphene in 2004, graphene and related materials have received intensive attention as promising materials for nanoelectronics because of their fascinating electrical, mechanical, and chemical properties.[5,6] In addition, the recent large-scale synthesis of highquality graphene films enables their use in bendable and/or stretchable transparent electrodes for solar cells, sensors, and displays. Surface grafting on graphene of functional materials will be an indispensable technique for these applications....
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