Author
X. Wang
Bio: X. Wang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Thin film & Amorphous carbon. The author has an hindex of 7, co-authored 15 publications receiving 1364 citations.
Papers
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TL;DR: In this article, the chemical state of oxygen, aluminum and zinc in Al-doped ZnO (ZAO) films was investigated by X-ray photoelectron spectroscopy (XPS), as well as the transition zone of the film-to-substrate, by auger electron spectrography (AES), showing that zinc remains mostly in the formal valence states of Zn2+.
1,180 citations
TL;DR: In this paper, the micro-Raman scattering spectra of the films were compared to the results obtained by annealing the as-deposited VO 2 (B) film and the surface of the annealed film consisted of three regions of the black V 6 O 13 region, the yellow VO 2(B) region and the white non-crystalline region.
153 citations
TL;DR: Tetrahedral amorphous carbon (ta-C) films have been prepared by filtered arc deposition (FAD) and the structure of the ta-C films was characterised by Raman Spectroscopy.
Abstract: Tetrahedral amorphous carbon (ta-C) films have been prepared by filtered arc deposition (FAD). The structure of the ta-C films was characterised by Raman Spectroscopy. The haemocompatibility of the formed films was studied by measurement of haemolysis ratio and observation of platelet adhesion. Compared with low-temperature isotropic pyrolytic carbon (LTI-carbon), which is being used as the material for artificial heart valves in clinical use at present, the ta-C films showed improved anticoagulation property. In order to understand the observed haemocompatibility results, the surface energy of the films was evaluated to analyse surface adsorption of human serum albumin (HSA) and human fibrinogen (HFG). However, it was found that the ta-C films are identical to LTI-carbon with respect to protein adsorption. It is believed that effective work function could be a reason for the observed variation in haemocompatibility between the ta-C films and LTI-carbon.
82 citations
TL;DR: In this paper, a trilayer magnetic structure, consisting of a heavy metal (Platinum) as a buffer, an ultrathin ferromagnet (Cobalt) as functional layer, and an antiferromagnetic insulator (Nickel oxide, NixOy) as capping, is a host of intriguing physical phenomena desirable for spintronics.
12 citations
TL;DR: In this article, a focused ion beam was applied to selectively illuminate patterned regions in a Pt/Co/MgO strip with perpendicular magnetic anisotropy, soften the illuminated areas, and realize the gradual magnetization switching by spin-orbit torque (SOT) driven nucleation process.
Abstract: Gradual magnetization switching driven by spin–orbit torque (SOT) is preferred for neuromorphic computing in a spintronic manner. Here we have applied focused ion beam to selectively illuminate patterned regions in a Pt/Co/MgO strip with perpendicular magnetic anisotropy, soften the illuminated areas, and realize the gradual switching by a SOT-driven nucleation process. It is found that a large in-plane field is helpful to reduce the nucleation barrier, increase the number of nucleated domains and intermediate states during the switching progress, and finally flatten the switching curve. We proposed a phenomenological model for descripting the current dependence of magnetization and the dependence of the number of nucleation domains on the applied current and magnetic field. This study may promote the birth of SOT devices applicable in neuromorphic computing applications.
12 citations
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TL;DR: BHJ solar cells are typically fabricated with a transparent conductive anode, a low-work-function metal cathode, and an active layer sandwiched between the anode and cathode.
Abstract: BHJ solar cells are typically fabricated with a transparent conductive anode (e.g. indium tin oxide, ITO), a low-work-function metal cathode (e.g., Al, Ca), and an active layer (a mixture of conjugated polymer and fullerene derivative) sandwiched between the anode and cathode. The BHJ layer and cathode dramatically affect the stability. In particular, the cathode is susceptible to degradation by oxygen and water vapor. Poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is often used as an anode buffer layer. Long-term stability is a problem because PEDOT:PSS is hygroscopic and acidic. [ 17–21 ]
1,449 citations
TL;DR: The ZnO with oxygen vacancies are found to be efficient for photodecomposition of 2,4-dichlorophenol under visible light irradiation and a narrowing bandgap can be confirmed by the enhancement of the photocurrent response when theZnO was irradiated with visible light.
Abstract: Oxygen vacancies in crystal have important impacts on the electronic properties of ZnO. With ZnO2 as precursors, we introduce a high concentration of oxygen vacancies into ZnO successfully. The obtained ZnO exhibits a yellow color, and the absorption edge shifts to longer wavelength. Raman and XPS spectra reveal that the concentration of oxygen vacancies in the ZnO decreased when the samples are annealed at higher temperature in air. It is consistent with the theory calculation. The increasing of oxygen vacancies results in a narrowing bandgap and increases the visible light absorption of the ZnO. The narrowing bandgap can be confirmed by the enhancement of the photocurrent response when the ZnO was irradiated with visible light. The ZnO with oxygen vacancies are found to be efficient for photodecomposition of 2,4-dichlorophenol under visible light irradiation.
1,213 citations
TL;DR: In this article, it was shown that the ratios of the different proteins adsorbed on the surface can be influenced by the addition of different elements into the diamond-like carbon (DLC) film.
650 citations
TL;DR: UV-vis spectra and photocatalytic results indicate that oxygen vacancies on STO surface play an important role in influencing the light absorption and photoc atalytic performance, however, an excess amount of oxygen vacancies leads to a decrease of photocatallytic performance.
Abstract: A facile and general method has been developed to fabricate oxygen vacancies on perovskite SrTiO3 (STO) nanocrystals through a controllable solid-state reaction of NaBH4 and SrTiO3 nanocrystals. STO samples with tunable color, oxygen vacancy concentration on nanocrystal surface have been synthesized. TEM results reveal that these STO samples have a crystalline core/amorphous shell structure (SrTiO3@SrTiO3–x). XPS and EPR results disclose that the oxygen vacancy concentration increases with the increase of reaction time and temperature. The concentration of oxygen vacancies calculated from TGA data, could reach 5.07% (atom) in this study. UV–vis spectra and photocatalytic results indicate that oxygen vacancies on STO surface play an important role in influencing the light absorption and photocatalytic performance. However, an excess amount of oxygen vacancies leads to a decrease of photocatalytic performance. The optimal photocatalytic activity for H2 production under UV–vis irradiation is up to 2.2 mmol h...
566 citations
TL;DR: A simple biogenic approach for the promotion of oxygen vacancies in pure zinc oxide (p-ZnO) nanostructures using an electrochemically active biofilm (EAB), which is different from traditional techniques for narrowing the band gap of nanomaterials, resulted in band gap narrowing of the ZnO nanostructure.
Abstract: Band gap narrowing is important and advantageous for potential visible light photocatalytic applications involving metal oxide nanostructures. This paper reports a simple biogenic approach for the promotion of oxygen vacancies in pure zinc oxide (p-ZnO) nanostructures using an electrochemically active biofilm (EAB), which is different from traditional techniques for narrowing the band gap of nanomaterials. The novel protocol improved the visible photocatalytic activity of modified ZnO (m-ZnO) nanostructures through the promotion of oxygen vacancies, which resulted in band gap narrowing of the ZnO nanostructure (Eg = 3.05 eV) without dopants. X-ray diffraction, UV-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, Raman spectroscopy, photoluminescence spectroscopy and high resolution transmission electron microscopy confirmed the oxygen vacancy and band gap narrowing of m-ZnO. m-ZnO enhanced the visible light catalytic activity for the degradation of different classes of dyes and 4-nitrophenol compared to p-ZnO, which confirmed the band gap narrowing because of oxygen defects. This study shed light on the modification of metal oxide nanostructures by EAB with a controlled band structure.
504 citations