Wafer-scale solution-derived molecular gate dielectrics for low-voltage graphene electronics

Graphene field-effect transistors are integrated with solution-processed multilayer hybrid organic-inorganic self-assembled nanodielectrics (SANDs). The resulting devices exhibit low-operating voltage (2 V), negligible hysteresis, current saturation with intrinsic gain > 1.0 in vacuum (pressure < 2 x 10-5 Torr), and overall improved performance compared to control devices on conventional SiO2 gate dielectrics. Statistical analysis of the field-effect mobility and residual carrier concentration demonstrate high spatial uniformity of the dielectric interfacial properties and graphene transistor characteristics over full 3 inch wafers. This work thus establishes SANDs as an effective platform for large-area, high-performance graphene electronics.

Transfer Printing Approach to All-Carbon Nanoelectronics

Transfer printing methods are used to pattern and assemble monolithic carbon nanotube (CNT) thin-film transistors on large-area transparent, flexible substrates. Airbrushed CNT thin-films with sheet resistance 1kOhmsquare^{-1} at 80% transparency were used as electrodes, and high quality chemical vapor deposition (CVD)-grown CNT networks were used as the semiconductor component. Transfer printing was used to pre-pattern and assemble thin film transistors on polyethylene terephthalate (PET) substrates which incorporated Al_{2}O_{3}/poly-methylmethacrylate (PMMA) dielectric bi-layer. CNT-based ambipolar devices exhibit field-effect mobility in range 1 - 33 cm^{2}/Vs and on/off ratio ~10^{3}, comparable to the control devices fabricated using Au as the electrode material.

Facile fabrication of suspended as-grown carbon nanotube devices

A simple scalable scheme is reported for fabricating suspended carbon nanotube field effect transistors (CNT-FETs) without exposing pristine as-grown carbon nanotubes to subsequent chemical processing. Versatility and ease of the technique is demonstrated by controlling the density of suspended nanotubes and reproducing devices multiple times on the same electrode set. Suspending the carbon nanotubes results in ambipolar transport behavior with negligible hysteresis. The Hooges constant of the suspended CNT-FETs (2.6 x 10-3) is about 20 times lower than for control CNT-FETs on SiO2 (5.6 x 10-2).