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Wearable strain sensors have attracted a great amount of attention for their plethora of potential applications, triggering ever growing interest in the search for low-cost materials and obtaining highly sensitive sensors. In this work, novel, flexible and highly sensitive strain sensors were fabricated using graphite granular films deposited on flexible substrates (PET, polyethylene terephthalate) by low-cost carbon-evaporation. The strain sensors show a fast response time of ≤140 ms, a high gauge factor (GF) of 1813, and a long durability of over 10 000 bending cycles. These low-cost, highly sensitive strain sensors have huge potential for applications in wearable electronics for health monitoring. [ABSTRACT FROM AUTHOR]

The transport properties of ZnO nanobelts along the 〈101̅0〉 non-polarized direction coupled with Cu electrodes were studied via non-equivalent Greens functions method and density functional theory formalism. The transport properties were greatly affected by interfacial spacing and nanobelt widths. The conductance decreased exponentially with the widths of the nanobelts. Ohmic behavior was found in narrow nanobelts, while rectifying characteristics were observed in wide nanobelts. In the case of narrow belts, the current–voltage characteristics were changed from ohmic type to rectifying characteristics as the interspace increased, corresponding to the contacts transforming from chemical to physical interactions. However, the conductance in the wider nanobelts declined exponentially as the interfacial distance increased. The change of metal induced gap states (MIGS) depends strongly on the interfacial distance but not significantly on the thickness of ZnO nanobelts. An n-type Schottky barrier between copper and ZnO nanobelts is induced by interfacial polarization effects. The Schottky barrier heights for the narrowest and widest nanobelts with equilibrium interfacial spacing were 0.37 eV and 0.44 eV, respectively, which is in good agreement with the experimental values. Additionally, the Schottky barrier heights increased almost linearly as the width of the nanobelts changed from 0.34 nm to 1.2 nm. [ABSTRACT FROM AUTHOR]

A transverse piezoelectric field-effect transistor (TP-FET) based on single ZnO nanobelts has been fabricated on a metallic graphite substrate in an atomic force microscope (AFM). The source-to-drain current of the TP-FET was found to decrease with increasing loading force under a positive bias due to the carrier-trapping effect and the creation of a charge-depletion zone. This TP-FET can be applied as a force/pressure sensor for measuring nanoNewton forces ranged from 0 to 700 nN.