Blockchain in supply chain management is expected to boom over the next five years. It is estimated that the global blockchain supply chain market would grow at a compound annual growth rate of 87% and increase from $45 million in 2018 to $3,314.6 million by 2023. Blockchain will improve business for all global supply chain stakeholders by providing enhanced traceability, facilitating digitisation, and securing chain-of-custody.This paper provides a synthesis of the existing challenges in global supply chain and trade operations, as well as the relevant capabilities and potential of blockchain. We further present leading pilot initiatives on applying blockchains to supply chains and the logistics industry to fulfil a range of needs. Finally, we discuss the implications of blockchain on customs and governmental agencies, summarize challenges in enabling the wide scale deployment of blockchain in global supply chain management, and identify future research directions.

S emiconductor nanowires are the fundamental materials for fabricating a wide range of nanodevices. 1Ϫ5 In the oxide family, ZnO nanowires and nanobelts have been widely studied as a key 1D oxide nanomaterial for numerous applications. Due to the unique piezoelectric and semiconducting coupled properties, a range of novel nanodevices of ZnO have been developed, such as nanogenerators, 6Ϫ9 piezoelectric field effect transistors, 10 piezoelectric diode, 11 and strain sensors. 12 A direct band gap of 3.4 eV and a large exciton binding energy (60 meV) at room temperature make ZnO a prominent candidate in optical applications, such as an ultraviolet detector, 13Ϫ16 optical pumped laser, 17,18 and light emitting diodes. 19 Recently, the photoconducting response at different degrees of straining of a ZnO nanowire has been studied using in situ transmission electron microscopy. 20 Although a lot of progress has been made in each research field as stated above, very limited research has been conducted on the localized and quantitatively controlled coupling of the piezoelectric effect and photoexcitation on a ZnO nanowire nanodevice.In this paper, by introducing a controllable stepping strain and using a focused laser beam, we have investigated the localized coupling between the piezoelectric effect and photoexcitation of ZnO microwire devices that exhibit various controlled electrical transport characteristics. By using microwire devices with SchottkyϪOhmic, OhmicϪOhmic, and SchottkyϪSchottky contacts, we have demonstrated the finetuning of contact characteristics, such as from Schottky to Ohmic or from Ohmic to Schottky, by varying the individual contributions made by piezoelectricity and photoexcitation at local contacts. On the basis of this concept, a design of electric transport properties is demonstrated. This study reveals a new principle for controlling the coupling among mechanical, electrical, and optical properties, which can be the basis for fabricating piezo-photonic-electronic nanodevices, which is referred to as piezophototronics. RESULTS AND DISCUSSIONOur device was fabricated using a single micro/nanowire of ZnO (see the Experimental Methods for details). First, we investigated the photoresponse of a microwire device with photoexcitation at different locations along the ZnO microwire. Figure 1a is a superimposed optical image taken from a ZnO microwire device with the laser spot focused at different positions, as schematically shown on the right-hand side. Points P1, P2, and P3, respectively, represent the positions at the left-hand metalϪZnO contact, central channel region, and right-hand metalϪZnO contact.

Using a metal-semiconductor-metal back-to-back Schottky contacted ZnO microwire device, we have demonstrated the piezoelectric effect on the output of a photocell. An externally applied strain produces a piezopotential in the microwire, which tunes the effective height of the Schottky barrier (SB) at the local contact, consequently changing the transport characteristics of the device. An equivalent circuit model together with the thermionic emission theory has explained the four kinds of relationships observed between the photocurrent and the applied strain. Our study shows the possibility of maximizing the output of a photocell by controlling strain in the device.

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In the published article, we cited reference 21 incorrectly, where the last name of the first author was incorrectly spelled and the last two authors were inadvertently omitted.The correct reference is Mougin, K.; Zheng, Z.; Piazzon, N.; Gnecco, E.; Haidara, H. Thermal Stability and Reconstruction of Nanoparticulate Au Film on Model Molecular Surfaces. J. Colloid Interface Sci. 2009, 333, 719Ϫ724.We note that this error has no impact on the final conclusions of the paper and also apologize to the authors of reference 21.