Switching Characteristics of Nanowire Feedback Field-Effect Transistors with Nanocrystal Charge Spacers on Plastic Substrates

In this study, we demonstrate the abruptly steep-switching characteristics of a feedback field-effect transistor (FBFET) with a channel consisting of a p^<i>+</i><i>–</i>i<i>–</i>n^<i>+</i> Si nanowire (NW) and charge spacers of discrete nanocrystals on a plastic substrate. The NW FBFET shows superior switching characteristics such as an on/off current ratio of ∼10⁵ and an average subthreshold swing (SS) of 30.2 mV/dec at room temperature. Moreover, the average SS and threshold voltage values can be adjusted by programming. These sharp switching characteristics originate from a positive feedback loop generated by potential barriers in the intrinsic channel area. This paper describes in detail the switching mechanism of our device

Enhancement of Trap-Assisted Green Electroluminescence Efficiency in ZnO/SiO₂/Si Nanowire Light-Emitting Diodes on Bendable Substrates by Piezophototronic Effect

The trap-assisted green electroluminescence (EL) efficiency of a light-emitting diode (LED) consisting of a ZnO nanowire (NW), a SiO₂ layer, and a Si NW on a bendable substrate is enhanced by piezophototronic effect. The green EL originates from radiative recombination through deep-level defects such as interstitial zinc, interstitial oxygen, oxygen antisite, and zinc vacancy in the component ZnO NW. The efficiency of the trap-assisted green EL is enhanced by a piezophototronic factor of 2.79 under a strain of 0.006%. The piezoelectric field built up inside the component ZnO NW improves the recombination rate of the electron–hole pairs thereby enhancing the efficiency of the trap-assisted green EL

Steep Subthreshold Swing n- and p‑Channel Operation of Bendable Feedback Field-Effect Transistors with p⁺–i–n⁺ Nanowires by Dual-Top-Gate Voltage Modulation

In this study, we present the steep switching characteristics of bendable feedback field-effect transistors (FBFETs) consisting of p⁺–i–n⁺ Si nanowires (NWs) and dual-top-gate structures. As a result of a positive feedback loop in the intrinsic channel region, our FBFET features the outstanding switching characteristics of an on/off current ratio of approximately 10⁶, and point subthreshold swings (SSs) of 18–19 mV/dec in the n-channel operation mode and of 10–23 mV/dec in the p-channel operation mode. Not only can these devices operate in n- or p-channel modes, their switching characteristics can also be modulated by adjusting the gate biases. Moreover, the device maintains its steep SS characteristics, even when the substrate is bent. This study demonstrates the promising potential of bendable NW FBFETs for use as low-power components in integrated circuits or memory devices

Modulation of the Dirac Point Voltage of Graphene by Ion-Gel Dielectrics and Its Application to Soft Electronic Devices

We investigated systematic modulation of the Dirac point voltage of graphene transistors by changing the type of ionic liquid used as a main gate dielectric component. Ion gels were formed from ionic liquids and a non-triblock-copolymer-based binder involving UV irradiation. With a fixed cation (anion), the Dirac point voltage shifted to a higher voltage as the size of anion (cation) increased. Mechanisms for modulation of the Dirac point voltage of graphene transistors by designing ionic liquids were fully understood using molecular dynamics simulations, which excellently matched our experimental results. It was found that the ion sizes and molecular structures play an essential role in the modulation of the Dirac point voltage of the graphene. Through control of the position of their Dirac point voltages on the basis of our findings, complementary metal–oxide–semiconductor (CMOS)-like graphene-based inverters using two different ionic liquids worked perfectly even at a very low source voltage (<i>V</i>_DD = 1 mV), which was not possible for previous works. These results can be broadly applied in the development of low-power-consumption, flexible/stretchable, CMOS-like graphene-based electronic devices in the future