Growth of Molybdenum Trioxide Nanoribbons on Oriented Ag and Au Nanostructures: A Scanning Electron Microscopy (SEM) Study

2019 ◽  
Vol 25 (6) ◽  
pp. 1449-1456 ◽  
Author(s):  
Paramita Maiti ◽  
Arijit Mitra ◽  
R. R. Juluri ◽  
Ashutosh Rath ◽  
Parlapalli V Satyam
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Molybdenum Trioxide ◽  
High Vacuum ◽  
Composite Films ◽  
Ultra High Vacuum ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Sem Study ◽  
Scanning Electron

AbstractWe report the growth of molybdenum trioxide (MoO3) nanoribbons (NRs) on epitaxial Ag and oriented Au nanostructures (NSs) using an ultra-high vacuum (UHV)-molecular beam epitaxy (MBE) technique at different substrate temperatures. An approximately 2 nm silver (Ag) film has been deposited at different growth temperatures (using UHV-MBE) on cleaned Si(100), Si(110), and Si(111) substrates. For faceted Au NSs, an approximately 50 nm Au film has been deposited (using high-vacuum thermal evaporation) on a Si(100) substrate with a native oxide layer at the interface and the sample was annealed in low vacuum (≈10−2) and at high temperature (≈975°C). Scanning electron microscopy measurements were performed to determine the morphology of MoO3/Ag and MoO3/Au composite films. From energy dispersive X-ray spectroscopy elemental mapping and line scans it is found that faceted Au NSs are more favorable for the growth of MoO3 NRs than epitaxial Ag microstructures.

The Performance of a Thermal Field Emission Gun

1975 ◽  
Vol 33 ◽  
pp. 146-147
Author(s):  
Dennis M. Maher ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Thermal Field ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Magnetic Alignment ◽  
Stable Operation ◽  
Alignment System ◽  
Scanning Electron

Although the "cold" field emission gun has been used successfully for both transmission and scanning electron microscopy it requires ultra-high vacuum which is not obtained easily when such a gun is interfaced to a conventional microscope system. Recently, the "thermal" field emission gun (TFEG) in which the emitting tip is held at around 1700°K has been proposed as an alternative electron source for such applications. Under this condition the tip is cleaned continuously, and surface asperities are smoothed, therefore stable operation is possible in a high vacuum. In this paper we report on the build-up characteristics, current stability and brightness of a TFEG which has been interfaced to a JEOL JEM 100B microscope equipped with a scanning attachment. The gun consists of a (111) tungsten emitter set on a rhenium filament, three anodes and a two stage magnetic alignment system. The gun chamber is ion pumped to a pressure in the range 6xl0-8 to 2xl0-9 torr.

Sublimation and Phase Transitions on Si(111) Surface Observed by Ultra High Vacuum Scanning Electron Microscopy

1998 ◽  
Vol 05 (03n04) ◽  
pp. 685-691 ◽  
Author(s):  
Yoshikazu Homma
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transition Temperature ◽  
High Vacuum ◽  
Ultrahigh Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Step ◽  
Current Direction ◽  
Step Flow ◽  
Scanning Electron

We studied the atomic step behavior on Si(111) during sublimation using ultrahigh vacuum scanning electron microscopy. A (111) plane with step spacings as large as several tens of micrometers could be obtained at the bottom of a crater by heating a vicinal Si(111) substrate with craters at around 1200°C in an ultrahigh vacuum. The step spacing on the plane was determined by nucleation of macrovacancies at the center of the plane while steps moved in a step flow manner, and was related to the adatom diffusion length. Above 1200°C, we found a transition-like increase in the step spacing. The electric current direction that induced step bunching changed at around the transition temperature. We attributed these phenomena to incomplete surface melting on the Si(111) surface. We also investigated the influence of heating current on the 7 × 7 phase transition using the wide Si(111) plane and found that the size of the 7 × 7 phase just below the transition temperature depended on the current direction.

An Experimental System Combining Medium Energy Electron Diffraction and Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 136-137
Author(s):  
J.M. Cowley ◽  
F.A. Koch ◽  
J.L. Albain
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
Experimental System ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Medium Energy ◽  
Pumping System ◽  
Scanning Electron

The theoretical and experimental advantages of using medium energy electrons (1-10 keV) instead of LEED and RHEED methods for quantitative surface studies were discussed by Moon and Cowley. A highly versatile ultra high vacuum system that exploits some of these advantages was constructed in our laboratory. The purpose of this paper is to describe design details of the instrument and to present initial data obtained.An overall view of the jinstrument is shown in Fig. 1. A commercially available field emission gun was attached to a Varian 240 LEED chamber. The pumping system is oil free and consists of cryosorbtion and Vaclon pumps.

Realization and Characterization of Graphene on 4H-SiC for Tera-Hertz Transistors

2015 ◽  
Vol 821-823 ◽  
pp. 941-944 ◽  
Author(s):  
Julien Pezard ◽  
Jeremy Lhuillier ◽  
Zakarya El-Friach ◽  
Véronique Soulière ◽  
Bertrand Vilquin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Effect ◽  
Field Effect Transistors ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Graphene Layers ◽  
Electrical Characterizations ◽  
Scanning Electron

Few layers graphene has been grown on 4H-SiC. Since this material has outstanding electronic properties, we aimed fabricating graphene field-effect transistors on silicon carbide wafer. Growth of the graphene layers was made by e-beam sublimation of silicium under ultra high vacuum (UHV). These layers were patterned and used as channels of transistors with source and drain made of P+ SiC. The different technological steps were checked through Raman spectroscopy, Scanning Electron Microscopy (SEM), and electrical characterizations.

Kaolinite dispersion in cassava starch-based composite films: a photonic microscopy and X-ray tomography study

2018 ◽  
Vol 38 (7) ◽  
pp. 641-647
Author(s):  
Jean Aimé Mbey ◽  
Fabien Thomas ◽  
Sandrine Hoppe
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dimethyl Sulfoxide ◽  
Polymer Matrix ◽  
Composite Films ◽  
Cassava Starch ◽  
X Ray ◽  
Clay Dispersion ◽  
Combined Use ◽  
Scanning Electron

Abstract In the present study, a combined use of photonic microscopy, scanning electron microscopy and 3D X-ray tomography is carried out in order to analyze the dispersion and the distribution of raw and dimethyl sulfoxide (DMSO)-intercalated kaolinite used as filler in cassava starch-based films. It is shown that the association of these techniques allows a valuable analysis of clay dispersion in polymer-clay composite films. In the case of kaolinite-starch composite films on which this study is focused, it is obvious that previous intercalation of kaolinite with DMSO is an efficient way to improve dispersion and distribution of kaolinite in a starch polymer matrix.

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