Early Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 2-3
Author(s):  
W.C. Nixon
Keyword(s):  
Electron Microscope ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Secondary Emission ◽  
Specimen Surface ◽  
Time Base ◽  
Transmission Electron ◽  
Cathode Ray Tube ◽  
Scanning Electron

The transmission electron microscope can be traced back to the work of K. Knoll and E. Ruska in Berlin who succeeded in 1931 in demonstrating a two lens electron microscope. The scanning electron microscope may also be traced back to the work of M. Knoll in 1935, during a study of secondary electron emission from surfaces. Two cathode ray tubes were used with a time-base generator supplying deflection signals to both tubes at once. The specimen under test was sealed into the first tube and the electron beam from the gun was scanned across the specimen surface and the variations in specimen current formed the signal. This signal was used to modulate the grid of the second cathode ray tube and the image displayed gave the variation in secondary emission on the specimen surface. In one case the word “Stuggart” was shown.

Thickness Dependence in Secondary Electron Emission from Carbon

1975 ◽  
Vol 33 ◽  
pp. 100-101
Author(s):  
D. Voreades
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Secondary Emission ◽  
Secondary Electrons ◽  
Emission Process ◽  
Backscattered Electrons ◽  
Escape Depth ◽  
Mode Of Operation ◽  
Scanning Electron

Secondary electrons are used in making topographical pictures of specimens in the scanning electron microscope. A better understanding of the secondary emission process will contribute in improving the resolution in this mode of operation.Recent experiments have indicated first that the escape depth of secondary electrons is a few atomic layers at the surface of the solid and second that the backscattered electrons are much more efficient in producing secondaries than the incoming ones. The results vary considerably. However, any model that one makes, for example similar to that of Jonker, consistent with these recent experimental results, will have the thickness as an important parameter.

Historical Introduction

1977 ◽  
Vol 35 ◽  
pp. 2-5
Author(s):  
R. D. Heidenreich
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
50Th Anniversary ◽  
Secondary Emission ◽  
Wave Nature ◽  
Nobel Prize In Physics ◽  
Primary Electrons ◽  
The U.S ◽  
Mutual Agreement

This program has been organized by the EMSA to commensurate the 50th anniversary of the experimental verification of the wave nature of the electron. Davisson and Germer in the U.S. and Thomson and Reid in Britian accomplished this at about the same time. Their findings were published in Nature in 1927 by mutual agreement since their independent efforts had led to the same conclusion at about the same time. In 1937 Davisson and Thomson shared the Nobel Prize in physics for demonstrating the wave nature of the electron deduced in 1924 by Louis de Broglie.The Davisson experiments (1921-1927) were concerned with the angular distribution of secondary electron emission from nickel surfaces produced by 150 volt primary electrons. The motivation was the effect of secondary emission on the characteristics of vacuum tubes but significant deviations from the results expected for a corpuscular electron led to a diffraction interpretation suggested by Elasser in 1925.

Application of WFS for Simultaneous Work Function and Secondary Electron Emission Measurement on Ba Covered Tungsten

2005 ◽  
Vol 473-474 ◽  
pp. 293-296
Author(s):  
György Vida ◽  
Ildikó Beck ◽  
V. Katalin Josepovits ◽  
Miklós Győr
Keyword(s):  
Work Function ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Secondary Emission ◽  
Operating Conditions ◽  
Emission Measurement ◽  
Pressure Discharge ◽  
Emission Yield ◽  
Burning Voltage

In the present paper the secondary emission and work function of W covered with different thickness Ba layers are compared. The secondary emission and work function were measured by Work Function Spectroscopy (WFS). It is clearly pointed out that the thin Ba coating causes the the enhancement of electron induced secondary electron emission. In high pressure discharge lamps high secondary emission and high thermionic current are required for reliable operating conditions, i.e., for reaching the nominal burning voltage and current etc. The results prove that the Ba spreading on the W surface from an alkali earth tungstate material is advantageous for lowering the work function and, simultaneously, for increasing the secondary emission yield.

Secondary Electron Emission Contrast of Quantum Wells in GaAs p-i-n Junctions

2009 ◽  
Vol 15 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Enrique Grunbaum ◽  
Zahava Barkay ◽  
Yoram Shapira ◽  
Keith W.J. Barnham ◽  
David B. Bushnell ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Wells ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Contrast Mechanisms ◽  
Novel Method ◽  
Profile Changes ◽  
Scanning Electron

AbstractThe secondary electron (SE) signal over a cleaved surface of GaAs p-i-n solar cells containing stacks of quantum wells (QWs) is analyzed by high-resolution scanning electron microscopy. The InGaAs QWs appear darker than the GaAsP barriers, which is attributed to the differences in electron affinity. This method is shown to be a powerful tool for profiling the conduction band minimum across junctions and interfaces with nanometer resolution. The intrinsic region is shown to be pinned to the Fermi level. Additional SE contrast mechanisms are discussed in relation to the dopant regions themselves as well as the AlGaAs window at the p-region. A novel method of in situ observation of the SE profile changes resulting from reverse biasing these structures shows that the built-in potential may be deduced. The obtained value of 0.7 eV is lower than the conventional bulk value due to surface effects.

Secondary electron emission from diamond: Physical modeling and application to scanning electron microscopy

2001 ◽  
Vol 89 (1) ◽  
pp. 689-696 ◽  
Author(s):  
P. Ascarelli ◽  
E. Cappelli ◽  
F. Pinzari ◽  
M. C. Rossi ◽  
S. Salvatori ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Emission ◽  
Physical Modeling ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Scanning Electron

New attempt to combine scanning electron microscopy and small-angle scattering in reciprocal space

2019 ◽  
Vol 52 (4) ◽  
pp. 783-790 ◽  
Author(s):  
Satoshi Koizumi ◽  
Satoru Ueda ◽  
Yukihiro Nishikawa ◽  
Takeshi Terao ◽  
Norio Kubo
Keyword(s):  
Electron Emission ◽  
Small Angle ◽  
Secondary Electron ◽  
Scattering Amplitude ◽  
Secondary Electron Emission ◽  
Small Angle Scattering ◽  
Reciprocal Space ◽  
Two Dimensional ◽  
Angle Scattering ◽  
Scanning Electron

An attempt has been made to combine small-angle scattering of X-rays or neutrons with scanning electron microscopy in reciprocal space, in order to establish a structural analysis method covering a wide range of sizes from micro- to macro-scales. A system with a binary contrast, in which scattering objects with a homogeneous density are dispersed in vacuum (or air), is considered. A topological surface image, detected by secondary electron emission, is converted by means of a Fourier transform into a two-dimensional scattering amplitude in reciprocal space. The method was first tested by studying a dilute system of monodisperse SiO2 particles, with respect to calibrations for brightness inversion, noise reduction and two-dimensional Fourier transform, to obtain a scattering amplitude that agrees well with the analytical amplitude for a spherical particle. Secondly, the microstructure of a carbon-supported Pt catalyst for polymer electrolyte fuel cell applications was examined with the combined method, covering length scales from 10 µm down to nanometres. After two-dimensional Fourier transformation, the secondary electron emission images with low magnification are able to overcome the limitation of the minimum wavenumber (q min) detectable by ultra-small-angle scattering.

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