XPS study on band alignment at PtO‐terminated ZnO(0001) interface

Kim, Tae‐Young; Yoshitake, Michiko; Yagyu, Shinjiro; Nemšák, Slavomír; Nagata, Takahiro; Chikyow, Toyohiro

doi:10.1002/sia.3601

Cited by 23 publications

(17 citation statements)

References 11 publications

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“…The E VBM (2.8–3.3 eV) and Φ (4.1 eV) values found for the sample without water after H* treatment agree very well with published values by Kim et al [35] ( Φ = 4.08 eV) after Ar + ion sputtering/heating ZnO single crystal at 700 °C, Gutmann et al [19] ( E VBM = 3.0 eV, Φ = 4.1 eV) on nanocrystalline ZnO surfaces after annealing at 400 °C in UHV environment, and Heinhold et al [21] ( E VBM = 3.41 eV) after annealing ZnO single crystal at 750 °C for 15 min. This agreement is not surprising since annealing or Ar + ion sputtering has similar effect of partial cleaning of ZnO as H* treatment.…”

Section: Resultssupporting

confidence: 90%

Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods

et al. 2017

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We report on the surface, sub-surface (top few nanometers) and bulk properties of hydrothermally grown zinc oxide (ZnO) nanorods (NRs) prior to and after hydrogen treatment. Upon treating with atomic hydrogen (H*), upward and downward band bending is observed depending on the availability of molecular H2O within the structure of the NRs. In the absence of H2O, the H* treatment demonstrated a cleaning effect of the nanorods, leading to a 0.51 eV upward band bending. In addition, enhancement in the intensity of room temperature photoluminescence (PL) signals due to the creation of new surface defects could be observed. The defects enhanced the visible light activity of the ZnO NRs which were subsequently used to photocatalytically degrade aqueous phenol under simulated sunlight. On the contrary, in the presence of H2O, H* treatment created an electronic accumulation layer inducing downward band bending of 0.45 eV (~1/7th of the bulk ZnO band gap) along with the weakening of the defect signals as observed from room temperature photoluminescence spectra. The results suggest a plausible way of tailoring the band bending and defects of the ZnO NRs through control of H2O/H* species.

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Section: Resultssupporting

confidence: 90%

Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods

et al. 2017

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“…These experiments yielded values between 4.45 eV and 4.50 eV. 24 The work function value found for the annealed surface (4.1 eV) agrees well with a published value by Kim et al 25 They measured a UPS derived work function of 4.08 eV on an Ar þ ion sputtered/heat treated (700 C) ZnO single crystal surface.…”

Section: Discussionsupporting

confidence: 75%

Work function measurements on nano-crystalline zinc oxide surfaces

Gutmann¹,

Conrad²,

Wolak³

et al. 2012

Journal of Applied Physics

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The work function of nano-crystalline zinc oxide (ZnO) thin films was examined using photoemission spectroscopy (PES). Colloidally dispersed ZnO nano-particles were electrospray-deposited in vacuum to form nano-crystalline thin films. The samples showed an immediate work function reduction by 0.35 eV during ultraviolet photoemission spectroscopy (UPS) measurements. This artifact was detected and quantified through low intensity x-ray photoemission spectroscopy (LIXPS) measurements, which use a very low photon flux. This prevented significant photochemical changes on the measured surface, i.e. the true work function unaffected by the UPS artifact can be measured. Annealing of an identical sample removed all ambient contamination from the ZnO surface with the effect to prevent the work function lowering artifact. This allowed the conclusion that ambient contamination is essential for the artifact to occur, similar to what was observed earlier on indium tin oxide and TiO2 surfaces. In an additional experiment, exposure of the annealed sample to the ambient resulted in a sample that again showed the artifact further demonstrating the necessity of water to be present. This experiment also demonstrated that the solubility enhancing surfactant shell of the nano-crystals does not play a significant role in the artifact, since it was removed during the annealing process.

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“…Continuity between coating and substrate indicated strong bonding force by MAO, and the Ag and Zn contents increased gradually from the substrate to the coating surface (Figure 13d). Ag was composed of 73% Ag 2 O and 27% metallic Ag [103,104], while Zn existed in the form of ZnO [105]. TEM images indicated that many large rutile or anatase grains of 20-40 nm in size (Figure 13e,f) and many relatively small Ag nano-grains with sizes of 5-10 nm (Figure 13f) were homogenously embedded in amorphous TiO 2 matrix.…”

Section: Introduction Of Both Metal Nanoparticles and Metallic Compoumentioning

confidence: 99%

Review of Antibacterial Activity of Titanium-Based Implants’ Surfaces Fabricated by Micro-Arc Oxidation

Zhang

Wang

et al. 2017

Coatings

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Ti and its alloys are the most commonly-used materials for biomedical applications. However, bacterial infection after implant placement is still one of the significant rising complications. Therefore, the application of the antimicrobial agents into implant surfaces to prevent implant-associated infection has attracted much attention. Scientific papers have shown that inorganic antibacterial metal elements (e.g., Ag, Cu, Zn) can be introduced into implant surfaces with the addition of metal nanoparticles or metallic compounds into an electrolyte via micro-arc oxidation (MAO) technology. In this review, the effects of the composition and concentration of electrolyte and process parameters (e.g., voltage, current density, oxidation time) on the morphological characteristics (e.g., surface morphology, bonding strength), antibacterial ability and biocompatibility of MAO antimicrobial coatings are discussed in detail. Anti-infection and osseointegration can be simultaneously accomplished with the selection of the proper antibacterial elements and operating parameters. Besides, MAO assisted by magnetron sputtering (MS) to endow Ti-based implant materials with superior antibacterial ability and biocompatibility is also discussed. Finally, the development trend of MAO technology in the future is forecasted.

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XPS study on band alignment at PtO‐terminated ZnO(0001) interface

Cited by 23 publications

References 11 publications

Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods

Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods

Work function measurements on nano-crystalline zinc oxide surfaces

Review of Antibacterial Activity of Titanium-Based Implants’ Surfaces Fabricated by Micro-Arc Oxidation

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