Graphene Cold Field-Emission Sources for Electron Microscopy Applications

2021 ◽  
pp. 289-313
Author(s):  
Anjam Khursheed ◽  
Xiuyuan Shao
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Emission Sources

scholarly journals What is the Dual-Detector FEG SEM, and Why use it?

1999 ◽  
Vol 7 (1) ◽  
pp. 14-15
Author(s):  
Steve Chapman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Imaging Systems ◽  
Emission Sources ◽  
The World ◽  
Dual Detector ◽  
User Friendly ◽  
Scanning Electron

The world of scanning electron microscopy seems to spin in such a way that every four years there is a dramatic step forward. Field emission sources (FEG), developed in the late 1960's, started life as a commercial disaster. In spite of the problems, certain manufacturers persisted with the first really user friendly FEG SEM reaching the market in the early 1980s. The FEG has been developed through the 1990's to be, without doubt, the source for SEU. But other advances in SEM performance have added to the instrument's performance, the most recent dramatic step being the introduction of semi-inlens imaging, a technique based upon 1980's dual detector imaging systems.

Sub-Nanometer Microscopy the Easy Way: An Underutilzed Tool for Reliability Assurance

1993 ◽  
Vol 309 ◽  
Author(s):  
Doug Hamilton ◽  
C. Colvard
Keyword(s):  
Electron Microscopy ◽  
Sample Preparation ◽  
Field Emission ◽  
Film Structure ◽  
Emission Sources ◽  
Plan View ◽  
Transmission Electron ◽  
Structure Thickness ◽  
Submicron Scale ◽  
Structural Aspects

AbstractScanning electron microscopy (SEM) is a frequently used tool for establishing reliability where potential causes of failure are related to structural aspects that show up on a submicron scale. Conventional SEMs, however, even those equipped with field emission sources, can provide high-quality photomicrographs only up to a magnification of about 100,000×. For many purposes greater resolution (several nanometers or below) is required, in which case the usual alternative is to turn to transmission electron microscopy (TEM), in spite of the laborious sample preparation required and limited plan-view images obtained. We describe here an underutilized alternative to TEM for many applications. The in-lens field emission SEM (ILFESEM) can provide pictures above 500,000× magnification with sub-nanometer resolution, with the simple sample preparation and surface viewing advantages of the SEM. Magnification in this range is necessary to verify modern day tolerances on surface morphology and roughness, oxide and thin film structure, thickness, and step coverage, and pore sizes in adhesion layers or diffusion membranes.

A New Image Processing Technique for STEM

1974 ◽  
Vol 32 ◽  
pp. 432-433
Author(s):  
Yasushi Kokubo ◽  
Hirotami Koike ◽  
Teruo Someya
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Scanning Electron Microscopy ◽  
Elastic Scattering ◽  
Field Emission ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Energy Analyzer ◽  
Scanning Microscope ◽  
Scanning Electron

One of the advantages of scanning electron microscopy is the capability for processing the image contrast, i.e., the image processing technique. Crewe et al were the first to apply this technique to a field emission scanning microscope and show images of individual atoms. They obtained a contrast which depended exclusively on the atomic numbers of specimen elements (Zcontrast), by displaying the images treated with the intensity ratio of elastically scattered to inelastically scattered electrons. The elastic scattering electrons were extracted by a solid detector and inelastic scattering electrons by an energy analyzer. We noted, however, that there is a possibility of the same contrast being obtained only by using an annular-type solid detector consisting of multiple concentric detector elements.

Blue Emitting BaAl2O4:Ce3+ Nanophosphors with High Color Purity and Brightness for White LEDs

2019 ◽  
Vol 25 (6) ◽  
pp. 1466-1470 ◽  
Author(s):  
Rituparna Chatterjee ◽  
Subhajit Saha ◽  
Karamjyoti Panigrahi ◽  
Uttam Kumar Ghorai ◽  
Gopes Chandra Das ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Sol Gel ◽  
Blue Emission ◽  
Diffraction Field ◽  
White Leds ◽  
Display Devices ◽  
Transmission Electron ◽  
Structure Morphology ◽  
The Impact

AbstractIn this work, strongly blue emitting Ce3+-activated BaAl2O4 nanophosphors were successfully synthesized by a sol–gel technique. The crystal structure, morphology, and microstructure of the nanophosphors have been studied by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The photoluminescence spectra show the impact of concentration variation of Ce3+ on the photoluminescence emission of the phosphor. These nanophosphors display intense blue emission peaking at 422 nm generated by the Ce3+ 5d → 4f transition under 350 nm excitation. Our results reveal that this nanophosphor has the capability to take part in the emergent domain of solid-state lighting and field-emission display devices.

Ultrahigh-Vacuum Electron Microscopy for Gold Nanostructures

2001 ◽  
Vol 7 (S2) ◽  
pp. 920-921
Author(s):  
Yukihito Kondo ◽  
Kimiharu Okamoto ◽  
Mikio Naruse ◽  
Toshikazu Honda ◽  
Mike Kersker
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Electronic Devices ◽  
Ultrahigh Vacuum ◽  
Gold Nanostructures ◽  
Scanning Tunneling ◽  
Nano Scale ◽  
Transmission Electron ◽  
Column Type ◽  
Schottky Type

Ultrahigh-vacuum transmission electron microscopy (UHVTEM) has become increasingly popular for the direct observation of nanostructures having clean surfaces, since industrial requirements to make and research nano-scale materials have been rapidly growing for quantum or nanoscale electronic devices. Since we have first developed high resolution UHVTEM in 1986, the UHVTEMs have been evolved with steady advances such as UHV compatible goniometer, field emission gun or etc. Furthermore, the UHVTEM started to combine analytical capabilities such as energy dispersive X-ray spectrometer, in-column type energy filter and etc., and to combine STM (scanning tunneling microscope). The UHV technology is essential for the analysis, because the portion of contaminant in a nano-scale specimen increases as the size of the specimen goes down. This paper reports the results of gold nanostructures by recently the developed UHVTEM.Figure 1 shows recently developed UHVTEM with Schottky type field emission gun.

scholarly journals A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Buzuayehu Abebe ◽  
Enyew Amare Zereffa ◽  
Aschalew Tadesse ◽  
H. C. Ananda Murthy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Field Emission ◽  
Volume Ratio ◽  
Electronic Configuration ◽  
Microscopic Investigation ◽  
Electron Microscopic ◽  
Active Materials ◽  
Scanning Electron

Abstract Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.

scholarly journals Thermoelectric Generator Using Polyaniline-Coated Sb2Se3/β-Cu2Se Flexible Thermoelectric Films

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1518
Author(s):  
Minsu Kim ◽  
Dabin Park ◽  
Jooheon Kim
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Thermoelectric Generator ◽  
Hydrothermal Reaction ◽  
Water Evaporation ◽  
Pani Film ◽  
Portable Devices ◽  
X Ray

Herein, Sb2Se3 and β-Cu2Se nanowires are synthesized via hydrothermal reaction and water evaporation-induced self-assembly methods, respectively. The successful syntheses and morphologies of the Sb2Se3 and β-Cu2Se nanowires are confirmed via X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and field emission transmission electron microscopy (FE-TEM). Sb2Se3 materials have low electrical conductivity which limits application to the thermoelectric generator. To improve the electrical conductivity of the Sb2Se3 and β-Cu2Se nanowires, polyaniline (PANI) is coated onto the surface and confirmed via Fourier-transform infrared spectroscopy (FT-IR), FE-TEM, and XPS analysis. After coating PANI, the electrical conductivities of Sb2Se3/β-Cu2Se/PANI composites were increased. The thermoelectric performance of the flexible Sb2Se3/β-Cu2Se/PANI films is then measured, and the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is shown to provide the highest power factor of 181.61 μW/m·K2 at 473 K. In addition, a thermoelectric generator consisting of five legs of the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is constructed and shown to provide an open-circuit voltage of 7.9 mV and an output power of 80.1 nW at ΔT = 30 K. This study demonstrates that the combination of inorganic thermoelectric materials and flexible polymers can generate power in wearable or portable devices.

Sign in / Sign up

Export Citation Format

Share Document