An improved design for an Scanning Tunnelling Microscope (STM) for use in a Transmission Electron Microscope (TEM)

1991 ◽  
Vol 49 ◽  
pp. 384-385
Author(s):  
W.K. Lo ◽  
J.C.H. Spence
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Mechanical Stability ◽  
Scanning Tunnelling Microscope ◽  
Reflection Mode ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Improved Design

An improved design for a combination Scanning Tunnelling Microscope/TEM specimen holder is presented. It is based on earlier versions which have been used to test the usefulness of such a device. As with the earlier versions, this holder is meant to replace the standard double-tilt specimen holder of an unmodified Philips 400T TEM. It allows the sample to be imaged simultaneously by both the STM and the TEM when the TEM is operated in the reflection mode (see figure 1).The resolution of a STM is determined by its tip radii as well as its stability. This places strict limitations on the mechanical stability of the tip with respect to the sample. In this STM the piezoelectric tube scanner is rigidly mounted inside the endcap of the STM holder. The tip coarse approach to the sample (z-direction) is provided by an Inchworm which is located outside the TEM vacuum.

An ultrahigh vacuum and ultrahigh resolution transmission electron microscope

1984 ◽  
Vol 42 ◽  
pp. 436-437
Author(s):  
M.L. McDonald ◽  
J.M. Gibson
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Ultrahigh Vacuum ◽  
Pole Piece ◽  
Ultrahigh Resolution ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Sample Chamber ◽  
Point To Point

Interest in ultrahigh vacuum (UHV) specimen environments in the transmission electron microscope (TEM) has grown considerably in recent years. The possibility of in-situ studies of atomically clean surfaces has been demonstrated by Yagi et.al., Wilson & Petroff & others. Most designs have involved a side entry specimen holder with cryopumping in the pole piece and are not easily compatible with ultrahigh resolution(UHR) due to size and stability requirements. We have designed a differentially pumped UHV specimen chamber for the JEOL 200CX (UHRTEM). It is intended to allow examination of clean thin specimens at pressures below 10-9 torr with a point to point resolution of 2.5 Å. Provisions for in-situ heating, cooling & deposition have been made. A unique part of this design is the relatively large volume sample chamber held at UHV (figsl&2). This design allows characterization of the atmosphere to which the sample is exposed & cleaning & preparation of samples out of the pole piece which is believed to be necessary for UHRTEM. Another possibility with this design is the transfer of a sample into the TEM from other chambers by use of a transfer case without exposing the sample to an atmosphere above 10-9 torr. Extra ports have been provided to accommodate future experiments.

Structure and symmetry of CaFeTi2O6 perovskite

1995 ◽  
Vol 53 ◽  
pp. 364-365
Author(s):  
Nan Yao ◽  
Alexandra Navrotsky ◽  
Kurt Leinenweber
Keyword(s):  
Electron Microscope ◽  
Liquid Nitrogen ◽  
Transmission Electron Microscope ◽  
Point Group ◽  
Carbon Film ◽  
Group Symmetry ◽  
Point Group Symmetry ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Calcium Iron

A new calcium iron (II) titanate ordered perovskite (CaFeTi2O6) was recently synthesized from an equimolar mixture of CaTiO3 and FeTiO3 at 12-15 GPa and 1200-1400 °C. In the present paper, we discuss the structure and symmetry studies of this new compound CaFeTi2O6 using CBED and HREM techniques. The CaFeTi2O6 powder sample was crushed to small fragments with an agate mortar and pestle under purified methanol. A drop of the resulting suspension was placed on a copper grid coated with holey-carbon film. CBED and HREM studies were performed on a Philips-CM20 ST transmission electron microscope equipped with a double tilt, liquid-nitrogen-cooled specimen holder under moderate vacuum conditions over the range from 10-6-10-7 Torr. CBED makes it possible to examine the diffraction symmetry of key orientations of the crystal and therefore determine the point-group symmetry of the crystal. This information, along with the dynamic extinction information on systematic absences, can be used to determine the crystallographic space group uniquely.

Observations of Surfaces by Electron Microscopy During STM Operation

1989 ◽  
Vol 159 ◽  
Author(s):  
J.C.H. Spence ◽  
U. Knipping ◽  
R. Norton ◽  
W. Lo ◽  
M. Kuwabara
Keyword(s):  
Digital Imaging ◽  
Imaging System ◽  
Scanning Tunnelling Microscope ◽  
Reflection Mode ◽  
Transmission Electron ◽  
Digital Imaging System ◽  
Scanning Tunnelling ◽  
Contrast Mechanism ◽  
First Results ◽  
Reflection Electron Diffraction

ABSTRACTA scanning tunnelling microscope is described which operates inside a transmission electron microscope in the reflection mode. The device is used to study the mechanism of STM contrast in graphite and semiconductors. It allows for the observation of any strain during tunnelling, using the reflection electron diffraction contrast mechanism. The first results of our new transputer-based digital imaging system for STM are reported.

2. Studying minerals

2014 ◽  
Author(s):  
David Vaughan
Keyword(s):  
Electron Microscope ◽  
Chemical Compositions ◽  
Scanning Tunnelling Microscope ◽  
X Ray Crystallography ◽  
Atomic Force ◽  
Transmission Electron ◽  
Reflected Light ◽  
Scanning Tunnelling ◽  
Electron Microscopes ◽  
Surface Chemistries

The study of minerals begins with their characterization, identification, and classification determined from their chemical compositions and crystallographic properties. ‘Studying minerals’ shows that historically this was based on properties observable in hand specimens, but the development of wide-ranging techniques has allowed the study of all aspects of minerals: their structures, chemistries, surface chemistries, and reactivities. Techniques described include transmitted light and reflected light microscopy using thin and polished sections; X-ray crystallography based on Bragg’s Law; techniques using various forms of electromagnetic radiation; and electron microscopes including the transmission electron microscope, scanning electron microscope, scanning tunnelling microscope, and atomic force microscope.

Use of an Energy Dispersive X-ray Spectrometer on a Transmission Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 60-61
Author(s):  
Roy H. Geiss ◽  
William A. Jesser
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Focal Length ◽  
Peak Height ◽  
Energy Dispersive ◽  
X Ray ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Specimen Height ◽  
Dispersive System

An Ortec Si(Li) energy dispersive X-ray detector designed for use on a Cambridge scanning electron microscope has been coupled to a Siemens transmission electron microscope by replacing the side tilt control on the Siemens by a brass tube as shown in figure 1. The Siemens specimen holder was modified to tilt the specimen approximately 20° from a horizontal position and to elevate it such that it is just visible to the detector through the side port. This increased specimen height requires an objective focal length of greater than 8 mm and consequently effects a lower resolution of the image, especially at low accelerating voltages. The peak/background in the X-ray spectra is best at 40kV, however, and deteriorates progressively with increasing accelerating voltage.Experiments similar to those of Fuchs, who employed a wavelength dispersive system on a Siemens TEM to measure film thickness, were repeated with the present energy dispersive system by analysing spectra from vacuum deposited gold films of various thicknesses. A linear relation between peak height and thickness was confirmed for several films up to 2000Å thick by comparing spectra from two adjacent grid squares, one covered by a single thickness of gold, the other covered by a double thickness, and noting that the peak heights were in the ratio of 1:2 to within a few percent.

Synthesis, Analysis, Transport and Field emission Measurements of Compound B-C-N Nanotubes

2003 ◽  
Vol 772 ◽  
Author(s):  
Dmitri Golberg ◽  
Yoshio Bando ◽  
Pavel Dorozhkin ◽  
Zhen-Chao Dong ◽  
Cheng-Chun Tang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Chemical Compositions ◽  
Scanning Tunnelling Microscope ◽  
Field Emission Properties ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Low Energy Electron ◽  
Electron Energy Loss

AbstractMultiwalled B-C-N nanotubes of various morphologies and chemical compositions were synthesized by reacting C-based nanotube templates with boron oxide and nitrogen at 1573 K- 2173 K. The nanotubes were thoroughly analysed using a high-resolution field-emission 300 kV transmission electron microscope (TEM), an energy-filtered field-emission 300 kV electron microscope (Omega filter), an electron energy loss spectrometer and an energy dispersion X-ray detector. Transport and field emission properties of the nanotubes were studied using a low energy electron point source microscope and via in-situ measurements in TEM equipped with a scanning tunnelling microscope (STM) unit.

A FIB Micro-Sampling Technique and a Site-Specific TEM Specimen Preparation Method for Precision Materials Characterization

2000 ◽  
Vol 636 ◽  
Author(s):  
Toshie Yaguchi ◽  
Ryoichi Urao ◽  
Takeo Kamino ◽  
Tsuyoshi Ohnishi ◽  
Takahito Hashimoto ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Ion Beam ◽  
Thin Foil ◽  
Specimen Preparation ◽  
Deep Trench ◽  
Site Specific ◽  
Area Of Interest ◽  
Specimen Holder ◽  
Transmission Electron

AbstractA technique to cut out small pieces of samples directly from chips or wafer samples in a focused ion beam (FIB) system has been developed. A deep trench is FIB milled to cut out a small, wedge-shaped portion of the sample from the area of interest A micromanipulator with tungsten (W) probe is employed for lifting the micro-sample. The lifted micro-sample is then mounted on a carrier to prepare electron transparent thin foil specimens for transmission electron microscope (TEM) observation. We have also developed a method for site-specific TEM specimen preparation. In this method, FIB system and TEM/scanning transmission electron microscope (STEM) equipped with secondary electron (SE) detector are employed. An FIB–TEM/STEM compatible specimen holder has also been developed so that a specimen can be milled in the FIB system and observed in a TEM/STEM without remounting the specimen. STEM and scanning electron microscopy (SEM) images are used for locating a specific site on a specimen. SEM image observation at an accelerating voltage of 200kV enabled us to observe not only surface structures but also inner structures near the surface of a cross section with depth of field of around 1 micrometer. The STEM image allows the observation of inner structures of 3-5 micrometer thick specimens. Milling of a specimen by FIB and observation of the milled sample by SEM and STEM are alternately carried out until an electron transparent thin foil specimen is obtained. The position accuracy of the method in TEM specimen preparation is approximately 100nm.

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