This special issue provides state-of-the-art coverage of the theoretical, scientific, and practical aspects related to flexible electronic skin.

We report on chemical vapor deposited (CVD) MoS2radio frequency (RF) transistors with a record fTof 20 GHz and fmaxof 11.4 GHz, and the largest high-field saturation velocity, νsat= 1.88 × 106cm/s, in MoS2reported so far. The gate-first approach, facilitated by cm-scale CVD MoS2, offers enhancement mode operation, ION/IOFFratio of 108, and the highest reported transconductance (gm) of 70 μS/μm. The intrinsic fT(fmax) obtained here is 3X (2X) greater than previously reported top-gated CVD MoS2RF FETs. With as-measured S-parameters, we demonstrate the design of a GHz MoS2-based RF amplifier. This amplifier has gain greater than 15 dB at 1.2 GHz, input return loss > 10 dB, bandwidth > 200 MHz, and DC power consumption of ~10 mW.

In this work, we provide an overview of the state-of-the-art flexible two dimensional radio frequency transistors based on graphene, MoS2 and black phosphorus for nanoelectronics applications from baseband to sub THz, with outstanding electrical performance obtained fulfilling the requirements of both high speed operation and low power consumptions. Flexible RF transistors based on graphene with intrinsic cutoff frequency (fT) reaching 100GHz enable sub-THz flexible nano systems. Large scale CVD grown MoS2 based flexible RF transistor was realized for the first time with record intrinsic fT ~ 5.6GHz which can afford low power RF nano systems. In addition, black phosphorus based flexible transistors and circuits have been realized with outstanding electrical performance in both DC and high frequency applications while retaining mechanical robustness.

It has been more than a decade since the early papers on graphene devices. Today, much progress has been achieved including material synthesis, device physics, and integrated circuits. All of this progress is particularly beneficial for flexible nanoelectronics where the high mobility of graphene can enable RF and microwave devices operating in the GHz regime. Here, we review the progress of flexible graphene transistors and circuits over the past decade. Recently, state of the art mobilities and GHz radio receiver systems have been demonstrated on plastic substrates.

This paper describes ultra-low-power chip design using nano-scale electro-mechanical switches (NEMS) with graphene. This chip is attachable and detachable onto the top of other chips due to remarkable stickiness of carbon-nanotube interconnects. New 3D-IC can be thus constructed for reconfigurable system-on-chips. Furthermore, due to a floating gate built in NEMS, their logic performance is much superior to that of NEMS-based logic in previous works, and even better than that of conventional CMOS.