Electron-Irradiation-Induced Crystallization of Amorphous Orthophosphates

AbstractAmorphous LaPO4, EuPO4, GdPO4, ScPO4, LuPO4, and fluorapatite [Ca5(PO4)3F] were irradiated by the electron beam in a transmission electron microscope. Irradiations were performed over a range of temperatures from −150 to 300 °C, electron energies from 80 to 200 keV, and current densities from 0.3 to 16 A/cm2. In all cases, the materials crystallized to form a randomly oriented polycrystalline assemblage. Crystallization is driven dominantly by inelastic processes, although ballistic collisions with the target nuclei can become important at energies higher than 175 keV, particularly in apatite. Using a high current density, crystallization is so fast that continuous lines of crystallites can be “drawn” on the amorphous matrix.

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Electron Beam Induced Nanometre Hole Formation and Surface Modification in Al, Si And MgO

MRS Proceedings ◽

10.1557/proc-157-323 ◽

1989 ◽

Vol 157 ◽

Cited By ~ 4

Author(s):

Tim J. Bullough ◽

C. J. Humphreys ◽

R. W. Devenish

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Transmission Electron Microscope ◽

Electron Probe ◽

High Current Density ◽

Rapid Development ◽

Atomic Scale ◽

Exit Surface ◽

Transmission Electron ◽

Stationary Electron

ABSTRACTA wide variety of materials which are normally undamaged when exposed to a lOOkeV electron beam in a conventional transmission electron microscope can be modified on a nanometre scale by the high current density electron probe in a dedicated scanning transmission electron microscope (STEM). A stationary 100keV STEM electron probe can produce holes typically l-5nm diameter through crystalline Al, Si and MgO tens of nanometres in thickness, while a scanned electron beam can smooth surfaces on an atomic scale.In Al the stationary electron probe in the STEM produces a row of facetted voids along the irradiated volume. The voids grow initially inwards from the electron exit surface, with each void typically 4nm in diameter and 12-24nm in length, separated by equal distances from one another. In contrast, continuous holes 1.2-1.6nm diameter form at the electron exit surface of Si when exposed to the focused electron beam. However, these holes form only at specific randomly distributed points separated from one another by 2-4nm over the surface of crystalline specimens of both n- and p-doped <001> and <111> Si.Square cross-section holes with widths of about lnm can be formed by the stationary electron probe in MgO crystals. Rastering the probe over a restricted area of MgO initially results in the rapid development of surface islands and channels which are subsequently removed to leave an atomically smooth surface.

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The Self-assembled Deposition on the Surface of Mono-crystalline Silicon Induced by High-Current Pulsed Electron Beam

High Temperature Materials and Processes ◽

10.1515/htmp-2015-0281 ◽

2017 ◽

Vol 36 (6) ◽

pp. 593-597

Author(s):

Zhang Conglin ◽

Guan Qingfeng ◽

Chen Jie ◽

Yan Pengcheng ◽

Lv Peng

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Crystalline Silicon ◽

High Current ◽

Pulsed Electron Beam ◽

Atomic Force ◽

Transmission Electron ◽

Si Nanoparticles ◽

Surface Microstructures ◽

Pulsed Irradiation

AbstractHigh-current pulsed electron beam (HCPEB) technique was applied to irradiate the surface of mono-crystalline silicon wafers. Surface microstructures of the irradiated surface were investigated in detail by atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The experimental results show that HCPEB irradiation with energy density 4 J/cm2 caused evaporation of the irradiated surface. Subsequently, the evaporation Si-droplets was deposited to form Si-nanoparticles on the surface. Meanwhile, the structures of intensive plastic deformation were also introduced within the irradiated surface layer. The dislocation configurations with rectangular and approximate hexagonal network were formed on the surface of Si wafer after 5-pulsed irradiation. The periodic self-deposited structures appear to be related to the configuration of regular dislocations arrays, which were favorable locations for the deposited Si-nanoparticles.

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Effect of high current density to defect generation of blue LED and its characterization with transmission electron microscope

Journal of Physics Conference Series ◽

10.1088/1742-6596/985/1/012023 ◽

2018 ◽

Vol 985 ◽

pp. 012023

Author(s):

R Gunawan ◽

E Sugiarti ◽

Isnaeni ◽

R I Purawiardi ◽

H Widodo ◽

...

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Current Density ◽

High Current Density ◽

High Current ◽

Blue Led ◽

Defect Generation ◽

Transmission Electron

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Microstructure Modifications and Associated Corrosion Improvements in GH4169 Superalloy Treated by High Current Pulsed Electron Beam

Journal of Nanomaterials ◽

10.1155/2015/876539 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5

Author(s):

Yichang Su ◽

Guangyu Li ◽

Liyuan Niu ◽

Shengzhi Yang ◽

Jie Cai ◽

...

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Optical Microscope ◽

High Current ◽

Pulsed Electron Beam ◽

Density Of Dislocations ◽

Nickel Based Superalloy ◽

Transmission Electron ◽

Gh4169 Superalloy ◽

Scanning Electron

The surface of the nickel-based superalloy GH4169 was subjected to high-current pulsed electron beam (HCPEB) treatment. The microstructural morphologies of the material were analysed by means of optical microscope (OP), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results reveal that the irradiated surface was remelted and many craters were formed. The density of craters decreased with the increment of HCPEB pulses. After 20-pulsed HCPEB irradiation, nanostructures were formed in the melted region of the surface. Furthermore, slipping bands and high density of dislocations were also formed due to the severe plastic deformation. The selective purification effect, homogenized composition, nanostructures, and dislocation slips introduced by HCPEB irradiation bring a significant improvement of corrosion resistance of GH4169 superalloy.

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Crystallization under 1 MeV Electron Beam Irradiation of Nanometer-Sized W-Dendrites Fabricated on Alumina Substrates with Electron-Beam-Induced Deposition

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.4035 ◽

2005 ◽

Vol 475-479 ◽

pp. 4035-4038 ◽

Cited By ~ 3

Author(s):

Ming Hui Song ◽

Kazutaka Mitsuishi ◽

Kazuo Furuya

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Transmission Electron Microscope ◽

Electron Beam Irradiation ◽

Transmission Electron ◽

Electron Beam Induced Deposition ◽

Dendritic Form ◽

Almost All ◽

Induced Crystallization ◽

Amorphous Part

Nanometer-sized W-dendritic form structure was fabricated with electron-beam-induced deposition (EBID) in a 200 kV transmission electron microscope. The as-prepared nanodendrites are composed of W-nanocrystals and amorphous. The as-prepared nanodendrites were then irradiated with 1 MeV electron beam in a high voltage transmission electron microscope. The effect of the irradiation is investigated. The irradiation transformed effectively almost all the amorphous part to crystalline state. Morphology of the nanodendrite also changes. The irradiation induced crystallization and morphology change are discussed.

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Aspects of microanalysis in a transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109690 ◽

1978 ◽

Vol 36 (1) ◽

pp. 510-511

Author(s):

R. Sinclair ◽

B.E. Jacobson

Keyword(s):

Grain Size ◽

Electron Beam ◽

Electron Microscope ◽

Chemical Analysis ◽

Transmission Electron Microscope ◽

Vapor Deposition ◽

Critical Currents ◽

X Ray ◽

Fine Grain ◽

Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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Automatic analysis of Kikuchi diffraction patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172231 ◽

1994 ◽

Vol 52 ◽

pp. 900-901

Author(s):

H. Weiland ◽

D. P. Field

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Spatial Resolution ◽

Relevant Information ◽

Crystalline Materials ◽

Large Size ◽

Transmission Electron ◽

New Type ◽

Diffraction Patterns ◽

Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

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Electron-beam damage of oxides at high current densities

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155141 ◽

1989 ◽

Vol 47 ◽

pp. 634-635

Author(s):

M. R. McCartney ◽

J. K. Weiss ◽

David J. Smith

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Current Density ◽

Transition Metal Oxides ◽

Time Resolved ◽

Rapid Acquisition ◽

Resolution Electron ◽

Current Densities ◽

Electron Stimulated Desorption ◽

Channel Analyzer

It is well-known that electron-beam irradiation within the electron microscope can induce a variety of surface reactions. In the particular case of maximally-valent transition-metal oxides (TMO), which are susceptible to electron-stimulated desorption (ESD) of oxygen, it is apparent that the final reduced product depends, amongst other things, upon the ionicity of the original oxide, the energy and current density of the incident electrons, and the residual microscope vacuum. For example, when TMO are irradiated in a high-resolution electron microscope (HREM) at current densities of 5-50 A/cm2, epitaxial layers of the monoxide phase are found. In contrast, when these oxides are exposed to the extreme current density probe of an EM equipped with a field emission gun (FEG), the irradiated area has been reported to develop either holes or regions almost completely depleted of oxygen. ’ In this paper, we describe the responses of three TMO (WO3, V2O5 and TiO2) when irradiated by the focussed probe of a Philips 400ST FEG TEM, also equipped with a Gatan 666 Parallel Electron Energy Loss Spectrometer (P-EELS). The multi-channel analyzer of the spectrometer was modified to take advantage of the extremely rapid acquisition capabilities of the P-EELS to obtain time-resolved spectra of the oxides during the irradiation period. After irradiation, the specimens were immediately removed to a JEM-4000EX HREM for imaging of the damaged regions.

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