Physical properties of nanometer graphene oxide films partially and fully reduced by annealing in ultra-high vacuum

2017 ◽  
Vol 122 (7) ◽  
pp. 075301 ◽  
Author(s):  
Glenn G. Jernigan ◽  
Jill A. Nolde ◽  
Nadeem A. Mahadik ◽  
Erin R. Cleveland ◽  
Janice E. Boercker ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Physical Properties ◽  
High Vacuum ◽  
Oxide Films ◽  
Ultra High Vacuum

scholarly journals Symmetry-Induced Structuring of Ultrathin FeO and Fe3O4 Films on Pt(111) and Ru(0001)

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 719
Author(s):  
Natalia Michalak ◽  
Zygmunt Miłosz ◽  
Gina Peschel ◽  
Mauricio Prieto ◽  
Feng Xiong ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Single Crystal ◽  
High Vacuum ◽  
Oxide Films ◽  
Ultra High Vacuum ◽  
Mutual Orientation ◽  
High Catalytic Activity ◽  
Plane Orientation ◽  
Metal Single Crystal ◽  
Iron Oxide Films

Iron oxide films epitaxially grown on close-packed metal single crystal substrates exhibit nearly-perfect structural order, high catalytic activity (FeO) and room-temperature magnetism (Fe3O4). However, the morphology of the films, especially in the ultrathin regime, can be significantly influenced by the crystalline structure of the used support. This work reports an ultra-high vacuum (UHV) low energy electron/synchrotron light-based X-ray photoemission electron microscopy (LEEM/XPEEM) and electron diffraction (µLEED) study of the growth of FeO and Fe3O4 on two closed-packed metal single crystal surfaces: Pt(111) and Ru(0001). The results reveal the influence of the mutual orientation of adjacent substrate terraces on the morphology of iron oxide films epitaxially grown on top of them. On fcc Pt(111), which has the same mutual orientation of adjacent monoatomic terraces, FeO(111) grows with the same in-plane orientation on all substrate terraces. For Fe3O4(111), one or two orientations are observed depending on the growth conditions. On hcp Ru(0001), the adjacent terraces of which are ‘rotated’ by 180° with respect to each other, the in-plane orientation of initial FeO(111) and Fe3O4(111) crystallites is determined by the orientation of the substrate terrace on which they nucleated. The adaptation of three-fold symmetric iron oxides to three-fold symmetric substrate terraces leads to natural structuring of iron oxide films, i.e., the formation of patch-like magnetite layers on Pt(111) and stripe-like FeO and Fe3O4 structures on Ru(0001).

An ultra high vacuum system for thin dielectric film deposition at low temperatures

1988 ◽  
Vol 3 (5) ◽  
pp. 951-957
Author(s):  
R. P. H. Chang ◽  
G. Griffiths
Keyword(s):  
Low Temperatures ◽  
High Vacuum ◽  
Oxide Films ◽  
Film Deposition ◽  
Ultra High Vacuum ◽  
Oxide Semiconductor ◽  
Vacuum System ◽  
Phosphorus Oxide ◽  
Electrical Measurements ◽  
Crystal Surfaces

An ultra high vacuum system has been designed and constructed for the purpose of depositing high-quality oxide films on well-characterized crystal surfaces at low temperatures. In particular, aluminum phosphorus oxide films have been deposited on both In P and Ge surfaces for the purpose of device application. Electrical measurements of metal-oxide-semiconductor structures show much improved interfacial properties with little or no hysteresis.

scholarly journals Microstructure and Optical Properties of E-Beam Evaporated Zinc Oxide Films—Effects of Decomposition and Surface Desorption

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3510
Author(s):  
Lukasz Skowronski ◽  
Arkadiusz Ciesielski ◽  
Aleksandra Olszewska ◽  
Robert Szczesny ◽  
Mieczyslaw Naparty ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Growth Direction ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Force Microscopy ◽  
Zinc Oxide Films

Zinc oxide films have been fabricated by the electron beam physical vapour deposition (PVD) technique. The effect of substrate temperature during fabrication and annealing temperature (carried out in ultra high vacuum conditions) has been investigated by means of atomic force microscopy, scanning electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. It was found that the layer deposited at room temperature is composed of Zn and ZnO crystallites with a number of orientations, whereas those grown at 100 and 200 ∘C consist of ZnO grains and exhibit privileged growth direction. Presented results clearly show the influence of ZnO decomposition and segregation of Zn atoms during evaporation and post-deposition annealing on microstructure and optical properties of zinc oxide films.

The Improved Passivation of Aluminum and Structure of Amorphous Alumina Formed on Aluminum During Oxidation in Various Environments

2000 ◽  
Vol 6 (S2) ◽  
pp. 38-39
Author(s):  
G. -W . Zhou ◽  
A. Kuznetsova ◽  
M. D. Bhardwaj ◽  
J. T. Yates ◽  
J. C Yang
Keyword(s):  
Electrochemical Impedance ◽  
High Vacuum ◽  
Oxide Films ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Ambient Temperatures ◽  
Passivation Film ◽  
Transmission Electron ◽  
Amorphous Alumina ◽  
Oxidation In Air

Nearly all metals form a passivation film due to oxidation in air at ambient temperatures, that acts as a diffusion barrier to protect the materials from further corrosion. Aluminum demonstrates excellent passivation behavior due to the formation of a protective amorphous alumina film during exposure to air at ambient temperatures. However, H. Ebinger and J. Yates discovered that the passivation of aluminum can be significantly improved by artificial oxidation. Both electron-beam induced oxidation in water vapor and oxidation in ozone atmospheres3 showed higher impedance in electrochemical impedance spectroscopy measurements to anion diffusion than the thermally grown oxides. To understand the nature of this beneficial passivation, we probed the microstructure of these amorphous oxide films by transmission electron microscopy (TEM).The oxide films were grown on a polycrystalline Al substrate. The Al substrate was cleaned with a sputter cleaner inside a UHV (ultra-high vacuum) system.

Band-like transport in high vacuum thermal reduced graphene oxide films

Vacuum ◽  
2019 ◽  
Vol 165 ◽  
pp. 254-261 ◽  
Author(s):  
L. Silipigni ◽  
G. Salvato ◽  
G. Di Marco ◽  
B. Fazio ◽  
A. Torrisi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Vacuum ◽  
Oxide Films ◽  
Reduced Graphene

Thin Pyrolytic Graphite Films for Electron Microscope Substrates

1971 ◽  
Vol 29 ◽  
pp. 226-227 ◽  
Author(s):  
George H. N. Riddle ◽  
Benjamin M. Siegel
Keyword(s):  
Vacuum Chamber ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Graphite Substrate ◽  
Nickel Substrate ◽  
Routine Procedure ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A routine procedure for growing very thin graphite substrate films has been developed. The films are grown pyrolytically in an ultra-high vacuum chamber by exposing (111) epitaxial nickel films to carbon monoxide gas. The nickel serves as a catalyst for the disproportionation of CO through the reaction 2C0 → C + CO2. The nickel catalyst is prepared by evaporation onto artificial mica at 400°C and annealing for 1/2 hour at 600°C in vacuum. Exposure of the annealed nickel to 1 torr CO for 3 hours at 500°C results in the growth of very thin continuous graphite films. The graphite is stripped from its nickel substrate in acid and mounted on holey formvar support films for use as specimen substrates.The graphite films, self-supporting over formvar holes up to five microns in diameter, have been studied by bright and dark field electron microscopy, by electron diffraction, and have been shadowed to reveal their topography and thickness. The films consist of individual crystallites typically a micron across with their basal planes parallel to the surface but oriented in different, apparently random directions about the normal to the basal plane.

A High Voltage Electron Microscopy Study of Sub-Oxide Formation in Vanadium

1971 ◽  
Vol 29 ◽  
pp. 212-213
Author(s):  
R. H. Geiss ◽  
R. L. Ladd ◽  
K. R. Lawless
Keyword(s):  
High Vacuum ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Ultra High Vacuum ◽  
Pure Oxygen ◽  
Pressure Oxidation ◽  
High Voltage Electron Microscopy ◽  
Oxidation Study ◽  
Voltage Electron ◽  
Good Agreement

Detailed electron microscope and diffraction studies of the sub-oxides of vanadium have been reported by Cambini and co-workers, and an oxidation study, possibly complicated by carbon and/or nitrogen, has been published by Edington and Smallman. The results reported by these different authors are not in good agreement. For this study, high purity polycrystalline vanadium samples were electrochemically thinned in a dual jet polisher using a solution of 20% H2SO4, 80% CH3OH, and then oxidized in an ion-pumped ultra-high vacuum reactor system using spectroscopically pure oxygen. Samples were oxidized at 350°C and 100μ oxygen pressure for periods of 30,60,90 and 160 minutes. Since our primary interest is in the mechanism of the low pressure oxidation process, the oxidized samples were cooled rapidly and not homogenized. The specimens were then examined in the HVEM at voltages up to 500 kV, the higher voltages being necessary to examine thick sections for which the oxidation behavior was more characteristic of the bulk.

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

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