Wafer-level and highly controllable fabricated silicon nanowire transistor arrays on （111） silicon-on-insulator （SOl） wafers for highly sensitive detection in liquid and gaseous environments

This paper presents a wafer-level and highly controllable fabrication technology for silicon nanowire field-effect transistor （SiNW-FET arrays） on （111） silicon- on-insulator （SOI） wafers. Herein, 3,000 SiNW FET array devices were designed and fabricated on 4-inch wafers with a rate of fine variety of more than 90% and a dimension deviation of the SiNWs of less than ＋ 20 nm in each array. As such, wafer-level and highly controllable fabricated SiNW FET arrays were realized. These arrays showed excellent electrical properties and highly sensitive determination of pH values and nitrogen dioxide. The high-performance of the SiNW FET array devices in liquid and gaseous environments can enable the detection under a wide range of conditions. This fabrication technology can lay the foundation for the large-scale application of SiNWs.

Vertical nanowires enhanced X-ray radiation damage of cells

Cell behavior is affected by nanostructured surface,but it remains unknown how ionizing radiation af-fects cells on nanostructured surface.This paper reports an experimental investigation of X-ray radiation induced damage of cells placed on an array of vertically aligned silicon nanowires.X-ray photoelectrons and secondary electrons produced from nanowire array are measured and compared to those from flat silicon substrate.The cell functions including morphology,viability,adhesion and proliferation have been examined and found to be drastically affected when cells are exposed to X-ray radiation,compared to those sitting on flat substrate and those only exposed to X-ray.The enhanced cell damage on nanowires upon X-ray exposure is attributed to nanowire enhanced production of photoelectrons including Auger electrons and secondary electrons,which have high escaping probability from sharp tips of nanowires.The escaped photoelectrons ionize water molecules and generate hydroxyl free radicals that can damage DNAs of cells.An inference of this work is that the contrast in scanning electron microscopy is useful in assessing the effects of nanomaterials for enhanced X-ray radiation therapy.

NOR logic function of a bendable combination of tunneling field-effect transistors with silicon nanowire channels

In this study, we propose a novel combination of tunneling field-effect transistors （TFETs） with asymmetrically doped p^＋-i-n^＋ silicon nanowire （SiNW） channels on a bendable substrate. The combination of two n-channel SiNW-TFETs （NWTFETs） in parallel and two p-channel NWTFETs in series operates as a two-input NOR logic gate. The component NWTFETs with the n- and p-channels exhibit subthreshold swings （SSs） of 69 and 53 mV·dec^-1, respectively, and the on/off current ratios are -106. The NOR logic operation is sustainable and reproducible for up to 1,000 bending cycles with a narrow transition width of -0.26 V. The mechanical bendability of the bendable NWTFETs shows that they are stable and have good fatigue properties. To the best of our knowledge, this is the first study on the electrical and mechanical characteristics of a bendable NOR logic gate composed of NWTFETs.