Characterization of Structural Changes and Defects in Ion Bombarded GaAs

1986 ◽  
Vol 82 ◽  
Author(s):  
Stephen T. Johnson ◽  
J.S. Williams ◽  
R.G. Elliman ◽  
A.P. Pogany ◽  
E. Nygren ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Amorphous Phase ◽  
Structural Changes ◽  
Extended Defects ◽  
Time Resolved ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Amorphous Phase Formation

ABSTRACTIn-situ time resolved reflectivity, Rutherford backscattering and channeling and transmission electron microscopy have been employed to characterise the evolution of Ar+ ion implantation damage in GaAs as a function of ion dose at various irradiation temperatures. Specific reflectivity signatures have been identified and characterised in terms of observed structural changes to the GaAs. Reflectivity provides a simple and convenient means of monitoring damage build up during ion implantation. In contrast to accepted models for amorphous phase formation in semiconductors, GaAs has been observed to undergo a sudden transformation from a crystal containing a dense network of extended defects to an amorphous phase under elevated temperature irradiation conditions.

Electrical and Structural Properties of MeV Si+ Ion Implantation in Silicon

1995 ◽  
Vol 378 ◽  
Author(s):  
Aditya Agarwal ◽  
S. Koveshnikov ◽  
K. Christensen ◽  
G. A. Rozgonyi
Keyword(s):  
Ion Implantation ◽  
Deep Level ◽  
Structural Defects ◽  
Extended Defects ◽  
Device Layer ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Current Voltage ◽  
Transient Spectroscopy ◽  
Si Ion Implantation

AbstractThe electrical properties of residual MeV ion implantation damage in Si after annealing from 600 to 1100°C for 1 hour have been investigated using Deep Level Transient Spectroscopy, Capaciatance-Voltage, and Current-Voltage measurements. These data have been correlated with structural defects imaged by Transmission Electron Microscopy. It is shown that at least 4 deep levels are associated with the buried layer of extended defects after annealing at 800, 900, 1000 and 1100°C. Additionally, for the wafer annealed at 800°C at least 5 more deep level centers are present in the device layer above the buried defects.

scholarly journals Imaging, understanding, and control of nanoscale materials transformations

MRS Bulletin ◽  
2021 ◽  
Author(s):  
Haimei Zheng
Keyword(s):  
Solid Electrolyte Interphase ◽  
Time Resolved ◽  
Nanocrystal Growth ◽  
Transmission Electron ◽  
Lithium Dendrites ◽  
Liquid Cell ◽  
Resolution Imaging ◽  
And Control

AbstractThe development of liquid cells for transmission electron microscopy has enabled breakthroughs in our ability to follow nanoscale structural, morphological, or chemical changes during materials growth and applications. Time-resolved high-resolution imaging and chemical analysis through liquids opened the opportunity to capture nanoscale dynamic processes of materials, including reaction intermediates and the transformation pathways. In this article, a series of work is highlighted with topics ranging from liquid cell developments to in situ studies of nanocrystal growth and transformations, dendrite formation, and suppression of lithium dendrites through in situ characterization of the solid–electrolyte interphase chemistry. The understanding garnered is expected to accelerate the discovery of novel materials for applications in energy storage, catalysis, sensors, and other functional devices.

In Situ Fabrication and Characterization of (NiCr)Al-Al2O3 Nanocomposite by Mechanical Alloying

2012 ◽  
Vol 16 ◽  
pp. 21-27 ◽  
Author(s):  
Amir Reza Shirani-Bidabadi ◽  
Ali Shokuhfar ◽  
Mohammad Hossein Enayati ◽  
Mazda Biglari
Keyword(s):  
Electron Microscopy ◽  
Mechanical Alloying ◽  
Structural Changes ◽  
Formation Mechanisms ◽  
Cross Sectional ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Powder Particles

In this research, the formation mechanisms of a (NiCr)Al-Al2O3 nanocomposite were investigated. The structural changes of powder particles during mechanical alloying were studied by X-ray difractometry (XRD) and the morphology and cross sectional microstructure of powder particles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The methodology involved mechanical alloying of NiO, Cr, and Al with molar ratios of 3:3:8. During mechanical alloying, NiO was first quickly reduced by aluminum atoms to produce NiAl nanocrystalline and Al2O3. Subsequently, and when a longer milling time was applied, chromium atoms diffused into the NiAl lattice. The heat treatment of this structure led to the formation of the (NiCr)Al intermetallic compound as well as Al2O3 with crystalline sizes of 23 nm and 58 nm, respectively.

Approaches to Exploring Spatio-Temporal Surface Dynamics in Nanoparticles with In Situ Transmission Electron Microscopy

2019 ◽  
Vol 26 (1) ◽  
pp. 86-94
Author(s):  
Ethan L. Lawrence ◽  
Barnaby D.A. Levin ◽  
Benjamin K. Miller ◽  
Peter A. Crozier
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Image Data ◽  
Dynamic Structure ◽  
Quantitative Information ◽  
Structure Property ◽  
Atomic Column ◽  
Time Resolved ◽  
Transmission Electron

AbstractMany nanoparticles in fields such as heterogeneous catalysis undergo surface structural fluctuations during chemical reactions, which may control functionality. These dynamic structural changes may be ideally investigated with time-resolved in situ electron microscopy. We have explored approaches for extracting quantitative information from large time-resolved image data sets with a low signal to noise recorded with a direct electron detector on an aberration-corrected transmission electron microscope. We focus on quantitatively characterizing beam-induced dynamic structural rearrangements taking place on the surface of CeO2 (ceria). A 2D Gaussian fitting procedure is employed to determine the position and occupancy of each atomic column in the nanoparticle with a temporal resolution of 2.5 ms and a spatial precision of 0.25 Å. Local rapid lattice expansions/contractions and atomic migration were revealed to occur on the (100) surface, whereas (111) surfaces were relatively stable throughout the experiment. The application of this methodology to other materials will provide new insights into the behavior of nanoparticle surface reconstructions that were previously inaccessible using other methods, which will have important consequences for the understanding of dynamic structure–property relationships.

In Situ TEM Observation of Defects and Amorphous Phase in Si Wafer During Ion Implantation

1991 ◽  
Vol 235 ◽  
Author(s):  
Naoto Shigenaka ◽  
Tuneyuki Hashimoto ◽  
Motomasa Fuse ◽  
Nobuo Owada ◽  
Hizuru Yamaguchi ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Amorphous Phase ◽  
Defect Density ◽  
Defect Layer ◽  
High Dose ◽  
In Situ Tem ◽  
High Dose Implantation ◽  
Amorphous Phase Formation ◽  
Si Wafer

ABSTRACTIn situ TEM observations of defects and. the amorphous phase in Si wafer during 150 keV Ar+ ion implantation were made which elucidated their characteristic behavior in Si. Defects introduced by ion implantation were eliminated by amorphous phase formation and then new defects did not form in the amorphous phase. Microstructural evolution in Si wafers under high dose implantation (2E16 ions/cm2) of 400 keV Si* ions was also investigated at temperatures of -70, -30, 20, 100 and 200 °C using a cross-section 1 TEM observation technique. At temperature of 20 °C and above, a defect layer was formed in each specimen, and the defect density was observed to decrease as temperature increased. At temperture of -30 °C and below the amorphous phase was formed and a defect layer which made contact with this phase was also observed. After annealing of these implanted specimens at 850 °C for 20 min, the amorphous phase had crystallized and the defect layer in contact with the amorphous phase was almost eliminated. But another defect layer was formed during annealing in the region where the amorphous phase had existed.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Dynamic studies of silicide-mediated crystallization of amorphous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1352-1353
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Metallic Phase ◽  
Single Crystal Substrate ◽  
Free Electrons ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

scholarly journals Preparation and Characterization of Epoxidised and Acrylated Styrene/Isoprene/Styrene (SIS) Triblock Block Copolymer Based Nanocomposites

2013 ◽  
Vol 28 ◽  
pp. 84-88 ◽  
Author(s):  
Santosh Khanal ◽  
Alina Shakya ◽  
Goerg H. Michler ◽  
Boulos Youssef ◽  
Jean M. Saiter ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Chemical Society ◽  
Performic Acid ◽  
Casting Method ◽  
Immiscible Polymers ◽  
Transmission Electron ◽  
Boehmite Nanoparticles ◽  
Solution Casting Method

In this work, a commercially available Styrene-Isoprene-Styrene (SIS)triblock copolymer was modified into epoxidised version (ESIS)using performic acid generated in situ from hydrogen peroxide and formic acid. The epoxidised sample was further acrylated to prepare acrylated version (ASIS). The nanocomposites of each sample (SIS, ESIS and ASIS) were prepared using boehmite nanoparticles as filler by solution casting method. The polymers were characterized by Fourier Transform Infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). TEM investigations revealed that that the epoxidation of the diene block enhanced the dispersion of the nanofiller in the polymer matrix while the segregation of the nanoparticles towards the interface of the immiscible polymers was observed in the acrylated block copolymer based nanocomposite. DOI: http://dx.doi.org/10.3126/jncs.v28i0.8112 Journal of Nepal Chemical Society Vol. 28, 2011 Page: 84-88 Uploaded Date: May 24, 2013

Sign in / Sign up

Export Citation Format

Share Document