•W nano-fuzzes microscopic evolution during annealing or He+ irradiated have been measured.•W nano-fuzzes are thermally unstable due to He release during annealing.•He are released from the top layer of W fuzzes by annealing.•Metastable W nano-fuzzes are formed due to He+ irradiation at an elevated temperature.W nano-fuzzes have been formed due to the large-flux and low-energy (200eV) He+ irradiation at W surface temperature of 1480 °C. Microscopic evolution of W nano-fuzzes during annealing or low-energy (200 eV) He+ bombardments has been observed using scanning electron microscopy and thermal desorption spectroscopy. Our measurements show that both annealing and He+ bombardments can significantly alter the structure of W nano-fuzzes. W nano-fuzzes are thermally unstable due to the He release during annealing, and they are easily sputtered during He+ bombardments. The current study shows that W nano-fuzzes act as a metastable state during low-energy and large-flux He+ irradiation at an elevated temperature.

•A novel homochiral MnIII(5-Brsalen) coordination polymer with left-handed helical character has been synthesized.•The molecular structure was determined by single-crystal X-ray diffraction.•UV–vis absorption spectrum, electrochemistry and magnetic properties of the compound have been studied.A novel homochiral manganese (III) Mn(5-Brsalen) coordination polymer with left-handed helical character by spontaneous resolution on crystallization by using Mn(5-Brsalen) and 4,4-bipyridine, [MnIII(5-Brsalen)(4,4-bipy)]·ClO4·CH3OH (1) (4,4-bipy = 4,4-bipyridine) has been synthesized and structurally characterized by X-ray single-crystal diffraction, elemental analysis and infrared spectroscopy. In compound 1, each manganese(III) anion is six-coordinate octahedral being bonded to four atoms of 5-Brsalen ligand in an equatorial plane and two nitrogen atoms from a 4,4-bipyridine ligand in axial positions. The structure of compound 1 can be described a supramolecular 2D-like structure which was formed by the intermolecular π-stacking interactions between the neighboring chains of the aromatic rings of 4,4-bipyridine and 5-Brsalen molecules. UV–vis absorption spectrum, electrochemistry and magnetic properties of the compound 1 have also been studied.A novel homochiral Mn(5-Brsalen) coordination polymer with left-handed helical character by spontaneous resolution on crystallization has been synthesized. The structure of the compound can be described a supramolecular 2D-like structure.

A large-power inductively coupled plasma source was designed to perform the continuous helium ions (He+) irradiations of polycrystalline tungsten (W) under International Thermonuclear Experimental Reactor (ITER) relevant conditions. He+ irradiations were performed at He+ fluxes of 2.3 × 1021–1.6 × 1022/m2 s and He+ energies of 12–220 eV. Surface damages and microstructures of irradiated W were observed by scanning electron microscopy. This study showed the growth of nano-fuzzes with their lengths of 1.3–2.0 μm at He+ energies of >70 eV or He+ fluxes of >1.3 × 1022/m2 s. Nanometer-sized defects or columnar microstructures were formed in W surface layer due to low-energy He+ irradiations at an elevated temperature (>1300 K). The diffusion and coalescence of He atoms in W surface layers led to the growth and structures of nano-fuzzes. This study indicated that a reduction of He+ energy below 12–30 eV may greatly decrease the surface damage of tungsten diverter in the fusion reactor.

•A novel cyano-bridged mixed-valence Fe(III)2Fe(II) chain has been synthesized.•The molecular structure was determined by single-crystal X-ray diffraction.•The long-range antiferromagnetic ordering was observed in the chain.A novel cyano-bridged mixed-valence Fe(III)2Fe(II) chain with long-range antiferromagnetic ordering [Fe(III)(Tp)(CN)3]2Fe(II)(CH3OH)2⋅2CH3OH (1) (Tp = Tris(pyrazolyl)hydroborate) has been synthesized. The molecular structure has been determined by single-crystal X-ray diffraction. In compound 1, the FeIII ion was coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp anions. Whereas, the FeII ion was surrounded by four cyanide nitrogen atoms and two oxygen atoms from two methanol molecules. The long-range antiferromagnetic ordering observed in complex 1 was presumably due to interchain magnetic dipolar interactions.

A novel 3D CuI-based tetrazole coordination polymer through the employment of in-situ hydrothermal techniques by using 4-cyanopyridine, NaN3 and CuI, [Cu5(L)3I2] (1) (HL = 5-(4-Pyridyl)-1H-tetrazole) has been synthesized and structurally characterized by X-ray single-crystal diffraction as well as by powder X-ray diffraction, elemental analysis and thermogravimetric analysis. In compound 1, each CuN3I tetrahedron, CuN2I2 tetrahedron and CuN3 triangle are linked to each other by L ligand to form a 3D framework structure. It is interesting to note that the interconnection of Cu1 and Cu2 ions by bridging L ligand form pseudo-porphyrin secondary building units. Surface photovoltage, field-induced surface photovoltage and luminescent properties of compound 1 have also been studied.A novel 3D CuI-based tetrazole coordination polymer through the employment of in-situ hydrothermal techniques by using 4-cyanopyridine, NaN3 and CuI has been synthesized. The compound has pseudo-porphyrin secondary building units. Surface photovoltage, field-induced surface photovoltage and luminescent properties of the compound have also been studied.

Low-energy (20–520 eV) hydrogen ion irradiations were performed at W surface temperature of 373–1073 K and a fluence ranging from 5.0 × 1023 to 1.0 × 1025/m2. Conductive atomic force microscopy (CAFM) as a nondestructive analytical technique was successfully used to detect irradiation-induced defects in polycrystalline W. The size and density of these nanometer-sized defects were strongly dependent on the fluence of hydrogen ions. Both ion energy (E) and temperature (T) play a crucial role in determining the ordering of nanometer-sized defects. Ordered arrangements were formed at relatively high E and T. This can be attributed to the stress-driven ripple effect of defect growth at crystal grains, resulting in the movement of W lattice along one certain crystal planes.

Near field magnetic force microscopy (NF-MFM) has been demonstrated to locally observe the magnetic fine structures in nanosized recording bits at an operating distance of 1 nm. The nanoscale magnetic domains, the polarity of surface magnetic charges, as well as the 3D magnetic fields leaking from the bits are investigated via NF-MFM with a soft NiFe tip. A Fourier analysis of the images suggests that the magnetic moment can be determined locally in a volume as small as 5 nanometers. The NF-MFM is crucial to the analysis of surface magnetic features and allows a wide range of future applications, for example, in data storage and biomedicine.

High-energy (260 keV) He+ pre-damaged and undamaged polycrystalline tungsten samples were irradiated with low-energy (220 eV) and high-flux (∼1021 ions/m2 s) He+ at a sample temperature of 873 K to a fluence of 1.0 × 1025 ions/m2. Microscopic evolution of these samples was carried out using non-destructive conductive atomic force microscopy and a nanohardness test. Analysis indicates that a large number of nanometer-sized protuberances of irradiated tungsten samples results from over-high internal pressure of nanometer-sized helium bubbles. Ordered and nanostructured helium bubbles with the same diameter and average spacing can be formed due to the self-trapping and self-organizing of helium atoms in the tungsten materials. In the case of pre-damaged, low-energy He+ irradiation results in a random distribution of nanostructured helium bubbles, indicating that high-energy He+ implantation results in serious irradiation damage of tungsten materials, acting as nuclei for helium bubbles.

ZnO thin films were grown on Si (111) substrates by low-pressure metal-organic chemical vapor deposition. The crystal structures and electrical properties of as-grown sample were investigated by scanning electron microscopy (SEM) and conductive atomic force microscopy (C-AFM). It can be seen that with increasing growth temperature, the surface morphology of ZnO thin films changed from flake-like to cobblestones-like structure. The current maps were simultaneously recorded with the topography, which was gained by C-AFM contact mode. Conductivity for the off-axis facet planes presented on ZnO grains enhanced. Measurement results indicate that the off-axis facet planes were more electrically active than the c-plane of ZnO flakes or particles probably due to lower Schottky barrier height of the off-axis facet planes.

Using a non-destructive conductive atomic force microscope combined with the Ar+ etching technique, we demonstrate that nanoscale and conductive He bubbles are formed in the implanted layer of single-crystalline 6H-SiC irradiated with 100 keV He+. We find that the surface swelling of irradiated SiC samples is well correlated with the growth of elliptic He bubbles in the implanted layer. First-principle calculations are performed to estimate the internal pressure of the He bubble in the void of SiC. Analysis indicates that nanoscale He bubbles acting as a captor capture the He atoms diffusing along the implanted layer at an evaluated temperature and result in the surface swelling of irradiated SiC materials.

•The brush-shape air plasma was efficient for large-area inactivation of E. coli cells.•The air plasma were able to have the strong oxidation effect on E. coli cells.•O and OH radicals and ozone molecules were supposed to play a crucial role.In this study, we designed one portable plasma device to generate a stable and brush-shape air discharge at atmospheric pressure for the plasma inactivation of Escherichia coli cells. The design of the portable plasma device based on the alignment of tens of air microplasmas resulted in the room-temperature and brush-shape plasma (50 mm in length and 5 mm in width). The brush-shape plasma was very efficient for the large-area inactivation of E. coli cells, and E. coli cells in direct contact with the air plasma were completely killed within the treatment time of 1 min. XPS analysis showed that the surface of plasma-activated E. coli cells was predominantly composed of C–O or C=O groups, indicating the oxygen-containing species in the air plasma were able to break the C–C or C–H bonds and cause the etching of organic compounds. Analysis indicated that lethal effects on E. coli cells were largely ascribed to the chemical erosion, i.e. damage to the cell wall or cell membrane. Analysis also indicated that both short-living species, such as O and OH radicals, and ozone molecules could play a crucial role in the plasma inactivation process by this method.

Polymer-like hydrocarbon films are irradiated with 100 keV He ion at the fluences of 1.0 × 1015–1.0 × 1017 ions/cm2 or at the irradiation temperature ranging from 25 to 600 °C. Conductive atomic force microscopy (CAFM) has been used to evaluate the nanoscale electron conducting properties of these irradiated hydrocarbon films. Nanoscale and conducting defects have been formed in the hydrocarbon films irradiated at a relatively high ion fluence (1.0 × 1017 ions/cm2) or an elevated sample temperature. Analysis indicates that He ion irradiation results in the evolution of polymer-like hydrocarbon into a dense structure containing a large fraction of sp2 carbon clusters. The sp2 carbon clusters formed in irradiated hydrocarbon films can contribute to the formation of filament-like conducting channels with a relatively high local field-enhancing factor. Measurements indicate that the growth of nanoscale defects due to He ion irradiation can result in the surface swelling of irradiated hydrocarbon films at a relatively high ion fluences or elevated temperature.

•The microplasma device is applied for coating deposition inside hollow-core fibers.•The microplasma device results in > 25 μm-thick carbon films.•The microplasma device is simple for deposition of ultralong carbon tubes.Ultrathick (> 25 μm) carbon films were obtained on the inner surface of hollow and micron-thick quartz fibers by confining CH4/He or C2H2/He microplasmas in their hollow cores. The resulting carbon films were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The microplasma-enhanced chemical vapor deposition (CVD) technique resulted in the uniform growth of amorphous carbon films on the inner surface of very long (> 1 m) hollow-core fibers. Film deposition is performed by using microplasmas at atmospheric pressure and at 50 Pa. The carbon films obtained with the latter show the smooth inner surfaces and the well continuity across the film/optical fiber. Low-pressure CH4/He and C2H2/He microplasmas can lead to a rapid growth (~ 2.00 μm/min) of carbon films with their thickness of > 25 μm. The optical emission measurements show that various hydrocarbon species were formed in these depositing microplasmas due to the collisions between CH4/C2H2 molecules and energetic species. The microplasma-enhanced CVD technique running without the complicated fabrication processes shows its potentials for rapidly depositing the overlong carbon tubes with their inner diameters of tens of microns.

By using an atmospheric pressure microplasma jet array device driven by a.c. voltage with repetition rate of several kilohertz, we were able to inactivate the resistant Pseudomonas sp HB1 cells in aqueous solution. Measurements showed that all Pseudomonas sp. cells in a suspension of 80 mL with the concentration of ~108 CFU (Colony-Forming Units) were killed within a treatment time of 6 min. Rather than O radicals, OH radicals or charged species were supposed to play the most important role in the plasma inactivation process by this method. This design can provide an effective mode of killing the resistant microorganism in water.

Fluorocarbon (FC) films have been deposited using pulsed and continuous wave (cw) radio frequency (rf) plasmas fed with hexafluoroethane (C2F6), octafluoropropane (C3F8), or octafluorocyclobutane (C4F8). The effects of feed gases used, discharge pressure, rf power, substrate positions and discharge modes (pulsed or cw) on the deposited films are examined. Film properties are determined using X-ray photoelectron spectroscopy, atomic force microscopy, and static contact angle measurements. The contact angles of FC films are well related to their compositions and structures. Feed gases used, discharge pressure, rf power, substrate positions and discharge modes strongly affect the morphology of the resulting film, as revealed by atomic force microscopy. Optical emission spectrometry measurements were performed to in-situ characterize the gas-phase compositions of the plasmas and radicals’ emission intensities during film deposition. Correlations between film properties, gas-phase plasma diagnostic data, and film growth processes were discussed. The film growth in pulsed or downstream plasmas was controlled by the surface migration of radicals, such as CF2 towards nucleation centers, which result in the deposition of FC films with less cross-linked nature and rougher surfaces. These results demonstrate that it is possible to control film compositions and surface structure by changing deposition parameters.

Fluorocarbon (FC) films deposited in continuous wave (cw) and pulsed difluoromethane radio frequency (r.f.) plasmas were characterized using Fourier transform infrared spectroscopy and atomic force microscopy. The effects of varying r.f. power, cw/pulsed discharge mode, and the distance of the substrate from the coil on the deposition rate, film structure, and surface roughness were investigated. These cw and pulsed deposition systems were characterized in-situ by means of optical emission spectroscopy. Emission intensities of Hα, Hβ, H2 and carbon-containing species in the coil region and downstream plasmas as a function of plasma parameters were measured. The hydrogen excitation temperature obtained from the relative emission intensities of Hα and Hβ lines shows a clear dependence on the r.f. power and the substrate position. Correlations between film properties, gas-phase plasma diagnostic data, and film growth processes were discussed. Experimental results indicate that the film growth within the coil region in cw plasmas is controlled by the synergistic effect between energetic ions and low-energy species. The film growth in pulsed and downstream plasmas is controlled by the growth of coalesced nuclei via surface diffusion of adsorbed species, which results in the deposition of FC films with relatively rough surfaces.

Dielectric barrier discharges have been used to deposit fluorocarbon (FC) films on various materials, such as paper, glass, and silicon substrates. The primary monomers used for plasma polymerization were difluoromethane (CH2F2), octafluoropropane (C3F8), and octafluorocyclobutane (C4F8). FC films were characterized using Fourier transform infrared spectroscopy, atomic force microscopy, static contact angle measurements, and scanning electron microscopy. Surface and structural properties of deposited films are strongly dependent on the plasma compositions and plasma parameters. FC films deposited on paper are to enhance its barrier properties and to achieve hydrophobic surfaces. Contact angle studies reveal that a minimum FC film thickness of about 200 nm on paper is required to completely cover surface and near-surface fibers, thereby providing the paper with long term hydrophobic character. In the C3F8 and C4F8 systems, the contact angles of the deposited films do not change appreciably with plasma parameters and are strongly dependent on the substrate roughness. Hydrogenated FC films deposited with CH2F2 plasmas show the relatively low contact angles due to the existence of CHX (x = 1–3) groups.

Both conductive atomic force microscopy (CAFM) and transmission electron microscopy have been used to characterize the defects or He bubbles in low-energy (120 eV) H and He irradiated tungsten (W). By a comparative study, we find that the current mapping from CAFM is very sensitive in the detection of nanometer-sized defects in low-energy H and He irradiated W. Our calculation confirms that the resistance change in H and He irradiated W is strongly affected by the distance between atomic force microscopy tip and defects/He bubbles. CAFM can accurately detect defects/He bubbles in the W surface layer, however, it is infeasible to measure them in the deep layer (>20 nm), especially due to the existence of defects in the surface layer.

Directly observing the magnetic domain behavior in patterned nanostructures is crucial to the investigation into advanced spin-based devices. Herein, we show that the magnetic vortex behavior can be deterministically observed and controlled in highly spin polarized La0.7Sr0.3MnO3 (LSMO) triangular dots by successive in-field magnetic force microscopy (MFM). Imaging the magnetic domains with MFM shows that most of the LSMO dots exhibit magnetic vortex states with a clockwise or anticlockwise “pinwheel” structure for decreasing the demagnetization energy. Probing the vortex chirality using in-field MFM indicates that the selective spin circulation of the triangular dots depends on the magnetic orientation of the bias nanomagnet with specially designed geometries. Comparison between measurement and simulation reveals that the vortex behavior should be governed by an interface involved pinning strength at the boundaries, as well as a geometrically induced shape anisotropy of the triangular dot, both of which result in shape-dominated magnetic domain reversals.