Electron beam projection nanopatterning using crystal lattice images obtained from high resolution transmission electron microscopy

High-resolution transmission electron microscopy (HRTEM) was used for examining Cd(S,Se) nanocrystals grown in silicate glasses commercially available as optical filters. The lattice images of the nanocrystals were numerated and submitted to filtering through Fourier transformation in order to sweep off the background signal originating mainly from glass. Optical filters from several firms were examined. The nanocrystals have been identified with Cd(S,Se) compounds crystallized in the wurzite structure, as in bulk material. The lattice images indicate crystallites having the shape of hexagonal prisms a little elongated along the c axis. The distribution of grain size differs according to the filter: the smallest size being about 1.5 nm (threshold for detection), the largest size varies from 7 to 10 nm, the average size sa , from 3–4 to 5–6 nm and the characteristic size sc from 5–6 to 7–8 nm (sc is the size of grains occupying the main part of the crystallized volume).

Download Full-text

Preparation of vermiculites for HRTEM

Clay Minerals ◽

10.1180/claymin.1989.024.1.02 ◽

1989 ◽

Vol 24 (1) ◽

pp. 23-32 ◽

Cited By ~ 12

Author(s):

CH. Marcks ◽

H. Wachsmuth ◽

H. Graf V. Reichenbach

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Computer Simulation ◽

High Resolution ◽

Alkyl Chains ◽

Transmission Electron ◽

Lattice Images ◽

Silicate Layers

AbstractA technique for preparing vermiculites for examination by high-resolution transmission electron microscopy (HRTEM) has been developed. A TEM-stable expanded phase can be obtained by intercalating n-alkylammonium ions between the silicate layers of a parent biotite. The vermiculite particles were embedded in Spurr resin and centrifuged to improve orientation. Ultra-thin specimens were prepared using an ultramicrotome, the quality and thickness of the sections being monitored by TEM. Lattice images of biotite, Ba-vermiculite and octylammonium-vermiculite, the latter showing a perpendicular arrangement of the alkyl chains relative to the silicate layers, were obtained with a resolution ∼2 Å. The reliability of these images was confirmed by computer simulation.

Download Full-text

Direct Observation of Defect Motion in Silicon By High-Resolution Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118667 ◽

1985 ◽

Vol 43 ◽

pp. 358-359

Author(s):

M. A. Parker ◽

R. Sinclair

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Beam ◽

High Resolution ◽

Crystal Defects ◽

Incident Electron Beam ◽

Transmission Electron ◽

Heating Effects ◽

Electron Beam Heating

Observations of defect motion by high resolution transmission electron microscopy (HRTEM) are rare. Unfortunately, the application of this technique has been limited to a few unique materials, those that can obtain sufficient thermal energy for the initiation of atomic motion through the heating effects of the incident electron beam. In earlier work, it was speculated that events such as the motion of crystal defects, observed in cadmium telluride (CdTe) with the electron beam heating method, might become evident in materials such as silicon (Si) if only sufficiently high temperatures could be achieved (∼ 600°C) in-situ.A silicon specimen with a suitable population of defects was chosen for examination; it consisted of a cross-section of.3 μ ﹛100﹜ silicon on ﹛1102﹜ sapphire (SOS from Union Carbide) which was implant amorphized by 28Si+ ion implantation at an energy of ∼ 170keV.

Download Full-text

Crystalline Particles in Thermally Grown Silicon Dioxide

MRS Proceedings ◽

10.1557/proc-14-201 ◽

1982 ◽

Vol 14 ◽

Author(s):

F. A. Ponce ◽

T. Yamashita

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Silicon Dioxide ◽

Silicon Layer ◽

Orientation Relationships ◽

Transmission Electron ◽

Lattice Images ◽

Thermally Grown

ABSTRACTSmall crystalline particles in the vicinity of the Si/SiO2 interface have been directly observed by high resolution transmission electron microscopy. These crystallites have typical diameters between 20 and 120 Å. Based on the observed interplanar spacings and angles in lattice images, the structure of these particles has been found to match those of cristobalite. Some orientation relationships also appear to exist between these particles and the silicon layer.

Download Full-text

Electron beam-induced surface modification and nano-engineering of carbon nanotubes: Single-walled and multiwalled

Journal of Materials Research ◽

10.1557/jmr.2006.0380 ◽

2006 ◽

Vol 21 (12) ◽

pp. 3109-3123 ◽

Cited By ~ 6

Author(s):

S. Gupta ◽

R.J. Patel ◽

R.E. Giedd

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Raman Spectroscopy ◽

Electron Beam ◽

Electron Microscope ◽

High Resolution ◽

Band Intensity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron

Influence of low and medium energy electron beam (E-beam) irradiation on the single-walled (SW) and multiwalled (MW) carbon nanotube films grown by microwave chemical vapor deposition are investigated. These films were subjected to electron beam energy of 50 keV from scanning electron microscope for 2.5, 5.5, 8.0, and 15 h and 100, 200, and 300 keV from transmission electron microscope electron gun for a few minutes to approximately 2 h continuously. To assess the surface modifications/structural degradation, the films were analyzed prior to and post-irradiation using x-ray diffraction and micro-Raman spectroscopy in addition to in situ monitoring by scanning and high-resolution transmission electron microscopy. A minimal increase in intertube or interplanar spacing (i.e., d002) for MW nanotubes ranging from 3.25–3.29 Å (∼3%) can be analogized to change in c-axis of graphite lattice due to thermal effects measured using x-ray diffraction. Resonance Raman spectroscopy revealed that irradiation generated defects in the lattice evaluated through variation of: the intensity of radial breathing mode (RBM), intensity ratio of D to G band (ID/IG), position of D and G bands and their harmonics (D* and G*). The increase in the defect-induced D band intensity, quenching of RBM intensity, and only a slight increase in G band intensity are some of the implications. The MW nanotubes tend to reach a state of saturation for prolonged exposures, while SW transforming semiconducting to quasi-metallic character. Softening of the q = 0 selection rule is suggested as a possible way to explain these results. It is also suggestive that knock-on collision may not be the primary cause of structural degradation, rather a local gradual reorganization, i.e., sp2+δ ⇔ sp2+δ, sp2 C seems quite possible. Experiments showed that with extended exposures, both kinds of nanotubes displayed various local structural instabilities including pinching, graphitization/amorphization, and forming intra-molecular junction (IMJ) within the area of electron beam focus possibly through amorphous carbon aggregates. They also displayed curling and closure forming nano-ring and helix-like structures while mending their dangling bonds. High-resolution transmission electron microscopy electrons corroborated these conclusions. Manufacturing of nanoscale structures “nano-engineering” of carbon-based systems is tentatively ascribed to irradiation-induced solid-state phase transformation, in contrast to conventional nanotube synthesis from the gas phase.

Download Full-text