Fully Printed Separated Carbon Nanotube Thin Film Transistor Circuits and Its Application in Organic Light Emitting Diode Control

The advantages of printed electronics and semiconducting single-walled carbon nanotubes (SWCNTs) are combined for the first time for display electronics. Conductive silver ink and 98% semiconductive SWCNT solutions are used to print back-gated thin film transistors with high mobility, high on/off ratio, and high current carrying capacity. In addition, with printed polyethylenimine with LiClO₄ as the gating material, fully printed top-gated devices have been made to work as excellent current switches for organic light emitting diodes (OLEDs). An OLED driving circuit composed of two top-gated fully printed transistors has been fabricated, and the successful control over external OLED is demonstrated. Our work demonstrates the significant potential of using printed carbon nanotube electronics for display backplane applications

Self-Aligned T-Gate High-Purity Semiconducting Carbon Nanotube RF Transistors Operated in Quasi-Ballistic Transport and Quantum Capacitance Regime

Carbon nanotube RF transistors are predicted to offer good performance and high linearity when operated in the ballistic transport and quantum capacitance regime; however, realization of such transistors has been very challenging. In this paper, we introduce a self-aligned fabrication method for carbon nanotube RF transistors, which incorporate a T-shaped (mushroom-shaped) aluminum gate, with oxidized aluminum as the gate dielectric. In this way, the channel length can be scaled down to 140 nm, which enables quasi-ballistic transport, and the gate dielectric is reduced to 2–3 nm aluminum oxide, leading to quasi-quantum capacitance operation. A current-gain cutoff frequency (<i>f</i>_t) up to 23 GHz and a maximum oscillation frequency (<i>f</i>_max) of 10 GHz are demonstrated. Furthermore, the linearity properties of nanotube transistors are characterized by using the 1 dB compression point measurement with positive power gain for the first time, to our knowledge. Our work reveals the importance and potential of separated semiconducting nanotubes for various RF applications

High-Power Coherent Microwave Emission from Magnetic Tunnel Junction Nano-oscillators with Perpendicular Anisotropy

The excitation of the steady-state precessions of magnetization opens a new way for nanoscale microwave oscillators by exploiting the transfer of spin angular momentum from a spin-polarized current to a ferromagnet, referred to as spin-transfer nano-oscillators (STNOs). For STNOs to be practical, however, their relatively low output power and their relatively large line width must be improved. Here we demonstrate that microwave signals with maximum measured power of 0.28 μW and simultaneously narrow line width of 25 MHz can be generated from CoFeB–MgO–based magnetic tunnel junctions having an in-plane magnetized reference layer and a free layer with strong perpendicular anisotropy. Moreover, the generation efficiency is substantially higher than previously reported STNOs. The results will be of importance for the design of nanoscale alternatives to traditional silicon oscillators used in radio frequency integrated circuits