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Interface engineering has emerged as a powerful approach for nanodevices performance manipulation. Nevertheless, most of previous work mainly focuses on interface modulation with single physical field, such as strain or light, little work has been reported on their coupling effect. Here, using patterned and polarity-controlled ZnO nanorods, the authors present a systematic multifield coupling investigation with photo-atomic force microscope, where an optical system is introduced and 355 nm UV laser with tunable power can precisely illuminate sample under conductive tip. Surface polarity-dependent tailoring of interfacial barrier is demonstrated, which verifies the dominant role of polar piezotronic effect. Furthermore, coupled modulation of piezopolarization and photoexcitation on local transport property is studied. Fine tuning of transport characteristics is achieved through subtly adjusting applied force and illumination power. The results offer an applicable method to realize tunable interface property with coupled external stimuli and can be potentially expanded to other noncentral symmetric structure nanowire or novel 2D layered piezoelectric materials. [ABSTRACT FROM AUTHOR]

Nowadays, the fabrication of photoanodes with high light-harvesting capability and charge transfer efficiency is a key challenge for photoelectrochemical (PEC) water splitting. In this paper, large-scale patterned ZnO nanorod arrays (NRAs) were designed and fabricated via two-beam laser interference lithography and hydrothermal synthesis, which were further applied as PEC photoanodes for the first time. By adopting the ZnO NRA photoanodes with square pattern, the PEC cells achieved a maximum efficiency of 0.18%, which was improved 135% compared to the control group with no patterned ZnO NRAs. The large-scale highly ordered ZnO NRAs have enhanced light-harvesting ability due to the light-scattering effect. In addition, the enlarged surface area of the patterned ZnO NRAs accelerated the charge transfer at the photoanode/electrolyte interface. This research demonstrates an effective mean to realize the efficient solar water splitting, and the results suggest that large-scale highly ordered nanostructures are promising candidates in the field of energy harvesting. [ABSTRACT FROM AUTHOR]

Developing photoanodes with high light-harvesting efficiency and great electronic transmission capacity remains a key challenge in photoelectrochemical (PEC) water splitting. In this paper, we reported an effective approach to enhance the PEC performance of ZnO nanowire arrays (NAs) photoanodes via overcoating ZnIn 2 S 4 nanosheets onto the ZnO surfaces. The ZnIn 2 S 4 electrocatalyst nanosheets were grown on the reduced graphene oxide (RGO) substrates by solvothermal synthesis and then grafted onto ZnO NAs, forming ZnO NAs/RGO/ZnIn 2 S 4 heterojunctions. The ZnIn 2 S 4 shells acted as visible light sensitizers, and the type-II band alignment between the ZnIn 2 S 4 shells and the ZnO cores contributed to charge separation and transport. Meanwhile, the introduction of RGO nanosheets largely increased the surface area and accelerated the PEC process by reducing the energy barrier of interfacial electrochemical reaction. As a result, over 200% enhancement of photo-to-hydrogen conversion efficiency was achieved from the ZnO NAs/RGO/ZnIn 2 S 4 heterojunctions compared to bare ZnO NAs. The results demonstrate that the RGO-based core/shell heterojunction arrays can provide a facile and compatible configuration for the potential applications in solar water splitting. [ABSTRACT FROM AUTHOR]

Abstract: Ultraviolet (UV) photodetectors (PDs) based on ZnO micro/nanowire (MNW) networks with Pt contacts have been fabricated on glass substrates. The PDs exhibited a high photosensitivity (5×103) for 365nm UV light with a fast recovery time (0.2s) at a reverse bias voltage of 2V. The light induced modulation of Schottky barrier and MNW–MNW junction barrier was employed to account for the results. It was also observed that the PD had a high on–off ratio of 800 without external bias. The photovoltaic effect was proposed to explain the self-powered phenomenon. [Copyright &y& Elsevier]

Abstract: A ZnO nanowire (NW) array ultraviolet photodetector (PD) with Pt Schottky contacts has been fabricated on a glass substrate. Under UV light illumination, this PD showed a high photo-to-dark current ratio of 892 at 30 V bias. Interestingly, it was also found that this PD had a high sensitivity of 475 without external bias. This phenomenon could be explained by the asymmetric Schottky barrier height (SBH) at the two ends causing different separation efficiency of photogenerated electron–hole pairs, which resulted in the formation of photocurrent. It is anticipated to have potential applications in self-powered UV detection field. [Copyright &y& Elsevier]

Abstract: In-doped ZnO nanostructures with four different morphologies, which are nanotetrapods, nanocombs, nanowires, and nanodisks, have been synthesized on silicon substrates by a simple thermal evaporation method. The XRD patterns show the In-doped ZnO nanostructures are all with the hexagonal wurtzite structure, and a slight difference in lattice parameters had been detected among the samples with various morphologies. The Raman spectra demonstrate that the vibrational mode of 2LA, which is very weak in undoped ZnO, was strongly enhanced with indium ion doping into ZnO structures. The photoluminescence (PL) measurements indicate that the nanodisks have a relative strong ultraviolet (UV) emission than other three kinds of samples. [Copyright &y& Elsevier]

Abstract: Vertically aligned S-doped ZnO nanorod arrays have been successfully synthesized by hydrothermal method at 90 °C for 2 h. The obtained nanorod is ∼70 nm in diameter and 1.2 μm in length. The XRD pattern and the Raman spectra indicate that the S-doped nanorod arrays are orientated at [001] and are single crystals with hexagonal wurtzite structure. The photoluminescence (PL) spectra show that S-doped ZnO nanorod arrays exhibit a relative weak ultraviolet (UV) emission, a violet emission and a strong green emission. The effects of S-doping on the structure and photoluminescence of ZnO nanorod arrays are discussed in detail. [Copyright &y& Elsevier]

Abstract: CNTs/T-ZnO/EP composites were fabricated using carbon nanotubes (CNTs) and tetrapod-shaped ZnO (T-ZnO) nanostructures as absorbents and epoxy resin (EP) as binder. The electromagnetic characteristics and microwave absorption properties of the composites were investigated in the frequency range of 2–18GHz. The influences of absorbents concentration and composite thickness on microwave absorption properties were studied. When the content of CNTs and T-ZnO nanostructures are 12wt% and 8wt%, respectively, and the composite thickness is 1.5mm, the value of the minimum reflection loss for CNTs/T-ZnO/EP composites is −23.00dB at 12.16GHz, and the bandwidth corresponding to reflection loss below −10dB is 5GHz. Moreover, the mechanism of microwave absorbing for CNTs/T-ZnO/EP composites was discussed. The results indicate that CNTs/T-ZnO/EP composites have the potential applications as microwave absorbents with the thin thickness and light weight. [ABSTRACT FROM AUTHOR]