Using a two-end bonded ZnO piezoelectric-fine-wire (PFW) (nanowire, microwire) on a flexible polymer substrate, the strain-induced change in I-V transport characteristic from symmetric to diode-type has been observed. This phenomenon is attributed to the asymmetric change in Schottky-barrier heights at both source and drain electrodes as caused by the strain-induced piezoelectric potential-drop along the PFW, which have been quantified using the thermionic emission-diffusion theory. A new piezotronic switch device with an "on" and "off" ratio of ∼120 has been demonstrated. This work demonstrates a novel approach for fabricating diodes and switches that rely on a strain governed piezoelectric-semiconductor coupling process.Binary switching is the principle of many electronic devices for applications such as data storage and logic circuits. Up to now most of the nanoscale switches are operated by an electrostatic force between a suspended carbon nanotube (CNTs)/nanowire and its counter electrode to switch between "on" and "off" depending on mechanical contact. [1][2][3] As the size of the devices reaching nanoscale, a small gap of ∼10 nm is required to be maintained between the CNTs/nanowire and the electrode for electro-mechanical switching. In such a case, the van der Waals interaction between the CNT and the electrode may be strong enough to bind the two together so that the device cannot perform the "off" function as required. Furthermore, the random thermal vibration at the tip of CNT may also become sufficiently large at conventional operating temperatures, which can strongly increase the device instability. 4 As a result, the reliability, lifetime and manufacturability of these devices are challenged.The Schottky barrier diode, a metal-semiconductor (MS) rectifying junction that generally exhibits switching effect, may overcome the drawbacks. ZnO, a material that exhibits semiconductor and piezoelectric properties, is likely a candidate for fabricating diode-based switching devices.Recently, various novel devices have been fabricated using ZnO nanowires/nanobelts by utilizing its coupled piezoelectric and semiconducting properties (piezotronic effect), such as nanogenerators, 5,6 piezoelectric field effect transistors and chemical sensors, 7,8 piezoelectric diodes, 9 triggers, 10 transducer and actuator, 11 and flexible piezotronic strain sensors. 12 In this letter, we report a new type flexible piezotronic switch device that is built using a single ZnO piezoelectric fine wire (PFW) (nanowire, microwire). Its operation mechanism relies on the piezoelectric potential induced asymmetric change in Schottky-barrier height (SBH) at the source and drain electrodes. The change of SBH is caused by the combined effects from strain-induced band structure change and piezoelectric potential. The device demonstrated here presents a new electromechanical switch built based on piezotronic effect. 13 For this study, the device was fabricated by bonding an ultralong ZnO PFW laterally on a polystyrene (PS) substrate,...

Light-field microscopy has emerged as a technique of choice for high-speed volumetric imaging of fast biological processes. However, artefacts, non-uniform resolution, and a slow reconstruction speed have limited its full capabilities for in toto extraction of the dynamic spatiotemporal patterns in samples. Here, we combined a view-channel-depth (VCD) neural network with light-field microscopy to mitigate these limitations, yielding artefact-free three-dimensional image sequences with uniform spatial resolution and high video-rate reconstruction throughput. We imaged neuronal activities across moving C. elegans and blood flow in a beating zebrafish heart at single-cell resolution with volumetric imaging rates up to 200 Hz.