High-speed, inkjet-printed carbon nanotube/zinc tin oxide hybrid complementary ring oscillators.

The materials combination of inkjet-printed single-walled carbon nanotubes (SWCNTs) and zinc tin oxide (ZTO) is very promising for large-area thin-film electronics. We compare the characteristics of conventional complementary inverters and ring oscillators measured in air (with SWCNT p-channel field effect transistors (FETs) and ZTO n-channel FETs) with those of ambipolar inverters and ring oscillators comprised of bilayer SWCNT/ZTO FETs. This is the first such comparison between the performance characteristics of ambipolar and conventional inverters and ring oscillators.

Utilizing carbon nanotube electrodes to improve charge injection and transport in bis(trifluoromethyl)-dimethyl-rubrene ambipolar single crystal transistors.

We have examined the significant enhancement of ambipolar charge injection and transport properties of bottom-contact single crystal field-effect transistors (SC-FETs) based on a new rubrene derivative, bis(trifluoromethyl)-dimethyl-rubrene (fm-rubrene), by employing carbon nanotube (CNT) electrodes. The fundamental challenge associated with fm-rubrene crystals is their deep-lying HOMO and LUMO energy levels, resulting in inefficient hole injection and suboptimal electron injection from conventional Au electrodes due to large Schottky barriers. Applying thin layers of CNT network at the charge injection interface of fm-rubrene crystals substantially reduces the contact resistance for both holes and electrons; consequently, benchmark ambipolar mobilities have been achieved, reaching 4.

Gate-tunable carbon nanotube-MoS2 heterojunction p-n diode.

The p-n junction diode and field-effect transistor are the two most ubiquitous building blocks of modern electronics and optoelectronics. In recent years, the emergence of reduced dimensionality materials has suggested that these components can be scaled down to atomic thicknesses. Although high-performance field-effect devices have been achieved from monolayered materials and their heterostructures, a p-n heterojunction diode derived from ultrathin materials is notably absent and constrains the fabrication of complex electronic and optoelectronic circuits.

Subnanowatt carbon nanotube complementary logic enabled by threshold voltage control.

In this Letter, we demonstrate thin-film single-walled carbon nanotube (SWCNT) complementary metal-oxide-semiconductor (CMOS) logic devices with subnanowatt static power consumption and full rail-to-rail voltage transfer characteristics as is required for logic gate cascading. These results are enabled by a local metal gate structure that achieves enhancement-mode p-type and n-type SWCNT thin-film transistors (TFTs) with widely separated and symmetric threshold voltages. These complementary SWCNT TFTs are integrated to demonstrate CMOS inverter, NAND, and NOR logic gates at supply voltages as low as 0.

Ambient-processable high capacitance hafnia-organic self-assembled nanodielectrics.

Ambient and solution-processable, low-leakage, high capacitance gate dielectrics are of great interest for advances in low-cost, flexible, thin-film transistor circuitry. Here we report a new hafnium oxide-organic self-assembled nanodielectric (Hf-SAND) material consisting of regular, alternating π-electron layers of 4-[[4-[bis(2-hydroxyethyl)amino]phenyl]diazenyl]-1-[4-(diethoxyphosphoryl) benzyl]pyridinium bromide) (PAE) and HfO2 nanolayers. These Hf-SAND multilayers are grown from solution in ambient with processing temperatures ≤150 °C and are characterized by AFM, XPS, X-ray reflectivity (2.

Inkjet Printing of High Conductivity, Flexible Graphene Patterns.

The ability to print high conductivity, conformal, and flexible electrodes is an important technological challenge in printed electronics, especially for large-area formats with low cost considerations. In this Letter, we demonstrate inkjet-printed, high conductivity graphene patterns that are suitable for flexible electronics. The ink is prepared by solution-phase exfoliation of graphene using an environmentally benign solvent, ethanol, and a stabilizing polymer, ethyl cellulose.

Aerosol jet printed, low voltage, electrolyte gated carbon nanotube ring oscillators with sub-5 μs stage delays.

A central challenge for printed electronics is to achieve high operating frequencies (short transistor switching times) at low supply biases compatible with thin film batteries. In this report, we demonstrate partially printed five-stage ring oscillators with >20 kHz operating frequencies and stage delays <5 μs at supply voltages below 3 V. The fastest ring oscillator achieved 1.