A Raman Scattering, Ion Channelling and Photoluminescence Study of Argon Ion Radiation Damage in Cu(Ga,In)Se2 - Dose Dependence and Dose Rate Effects

1998 ◽  
Vol 540 ◽  
Author(s):  
G. Lippold ◽  
K. Weinert ◽  
M.V. Yakushev ◽  
R.D. Pilkington ◽  
K. Otte ◽  
...  
Keyword(s):  
Dose Rate ◽  
Radiation Damage ◽  
High Efficiency ◽  
Defect Density ◽  
Lattice Structure ◽  
Dose Range ◽  
Damage Mechanism ◽  
Dose Dependence ◽  
Beam Current Density ◽  
Ion Channeling

AbstractThe ternary chalcopyrite semiconductor CuInSe2 and related ternary compounds are promising materials for the production of high-efficiency thin film solar cells. In this paper we study the dose dependence of ion radiation damage produced by 30 keV and 80 keV Ar ions in single crystals and polycrystalline films of Cu(In,Ga)Se 2 over a wide dose range from 1012 to 1017 cm-2, using Raman spectroscopy and ion channeling measurements. For the first time, we also report on the dose rate dependence with a variation of the beam current density in the range 0.44 to 44 µcm-2. Even for low damage levels no significant dependence of the defect concentration or damage mechanism on the dose rate could be observed. From phonon correlation length considerations we estimate defect densities. They are in agreement with ion channeling data obtained in the 1015 to 1016 dose range, where the breakdown of the lattice structure occurs. In this dose range, the defect density is close to the concentration of implanted atoms. We conclude, that this high impurity concentration is responsible for the amorphization.

Defect Tails in GE Implanted Si Probed by Slow Positrons and Ion Channeling

1998 ◽  
Vol 532 ◽  
Author(s):  
A P Knights ◽  
A Nejim ◽  
N P Barradas ◽  
R Gwilliam ◽  
P G Coleman ◽  
...  
Keyword(s):  
Dose Rate ◽  
Depth Distribution ◽  
Incident Angle ◽  
Dose Range ◽  
Positron Annihilation Spectroscopy ◽  
Average Dose ◽  
Ion Channeling ◽  
Open Volume ◽  
Volume Defect ◽  
Block Distribution

ABSTRACTPositron annihilation spectroscopy has been used to profile the distribution of defects following implantation of 120keV Ge+ into (100) Si in the dose range l x 1010 - lx104 cm−2 . The openvolume defect profiles can be adequately fitted assuming a simple rectangular block distribution extending to 350nm. Using anodic oxidation and etching, a procedure is described which allows details of the defect tails beyond the range of the implanted ion, usually inaccessible to positron -2 annihilation measurements, to be determined. For a time averaged dose-rate (Jr) of 0.02μA cm−2 and incident angle of 7°, open-volume defects are found to exist at concentrations exceeding 1016cm−3 at depths upto 600nm whereas the peak of the depth distribution of the implanted ions (Rp) is 76nm, measured using SIMS. When the time-average dose-rate is increased by a factor of 10, defects persist at concentrations in excess of 1017cm−3 beyond lμm and the Rp increases to 101nm. The open-volume defect profiles are compared to those deduced from Rutherford backscattering-channeling using the fitting routine DICADA.

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

Improvement in Wide-Gap A-SI:H For High-Efficiency Solar Cells

1992 ◽  
Vol 258 ◽  
Author(s):  
Sadaji Tsuge ◽  
Yoshihiro Hishikawa ◽  
Shingo Okamoto ◽  
Manabu Sasaki ◽  
Shinya Tsuda ◽  
...  
Keyword(s):  
Solar Cells ◽  
Plasma Treatment ◽  
High Efficiency ◽  
Defect Density ◽  
Hydrogen Plasma ◽  
Wide Band ◽  
Open Circuit ◽  
Wide Band Gap ◽  
High Efficiency Solar Cells ◽  
Wide Gap

ABSTRACTA hydrogen-plasma treatment has been used for the first time to fabricate wide-gap, high-quality a-Si:H films. The hydrogen content (CH) of a-Si:H films substantially increases by the hydrogen-plasma treatment after deposition, without deteriorating the opto-electric properties of the films. The photoconductivity (σph) of ≥ 10-5 ο-1 cm-1, photosensitivity ( σ ph/σ d) of > 106 and SiH2/SiH of <0.2 are achieved for a film with CH of ∼25 atomic >%. The optical gap of the film is > 1.70 eV by the (α h ν )1/3 plot, and is >2 eV by the Tauc's plot. The open circuit voltage of a-Si solar cells exceeds 1 V conserving the fill factor of > 0.7 when the wide-gap a∼Si:H films are used as the i-layer, which proves the wide band gap and low defect density.

scholarly journals Dose dependence of radiation damage in nano-structured amorphous SiOC/crystalline Fe composite

2015 ◽  
Vol 4 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Qing Su ◽  
Lloyd Price ◽  
Lin Shao ◽  
Michael Nastasi
Keyword(s):  
Radiation Damage ◽  
Dose Dependence

Morphological and structural evolution of WS2 nanosheets irradiated with an electron beam

2015 ◽  
Vol 17 (4) ◽  
pp. 2678-2685 ◽  
Author(s):  
Yuqing Wang ◽  
Yi Feng ◽  
Yangming Chen ◽  
Fei Mo ◽  
Gang Qian ◽  
...  
Keyword(s):  
Electron Beam ◽  
Radiation Damage ◽  
Structural Evolution ◽  
Damage Mechanism ◽  
P Movement ◽  
Ws2 Nanosheets

Movement of atoms and the radiation damage mechanism in irradiated WS2 nanosheets.

Raman and ion channeling analysis of damage in ion‐implanted GaAs: Dependence on ion dose and dose rate

1992 ◽  
Vol 71 (6) ◽  
pp. 2591-2595 ◽  
Author(s):  
U. V. Desnica ◽  
J. Wagner ◽  
T. E. Haynes ◽  
O. W. Holland
Keyword(s):  
Dose Rate ◽  
Ion Channeling ◽  
Ion Implanted

scholarly journals A STUDY ON RADIATION DAMAGE MECHANISM IN PbWO4 SCITILLATING CRYSTALS

1999 ◽  
Vol 48 (7) ◽  
pp. 1282
Author(s):  
FENG XI-QI ◽  
HAN BAO-GUO ◽  
HU GUAN-QIN ◽  
ZHANG YAN-XING
Keyword(s):  
Radiation Damage ◽  
Damage Mechanism

scholarly journals RNA protects a nucleoprotein complex against radiation damage

2016 ◽  
Vol 72 (5) ◽  
pp. 648-657 ◽  
Author(s):  
Charles S. Bury ◽  
John E. McGeehan ◽  
Alfred A. Antson ◽  
Ian Carmichael ◽  
Markus Gerstel ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Rna Binding ◽  
Dose Range ◽  
Protein Molecule ◽  
Highly Sensitive ◽  
Structure Determinations ◽  
Binding Pockets ◽  
Radiation Induced ◽  
Damage Susceptibility ◽  
Dna Complex

Radiation damage during macromolecular X-ray crystallographic data collection is still the main impediment for many macromolecular structure determinations. Even when an eventual model results from the crystallographic pipeline, the manifestations of radiation-induced structural and conformation changes, the so-called specific damage, within crystalline macromolecules can lead to false interpretations of biological mechanisms. Although this has been well characterized within protein crystals, far less is known about specific damage effects within the larger class of nucleoprotein complexes. Here, a methodology has been developed whereby per-atom density changes could be quantified with increasing dose over a wide (1.3–25.0 MGy) range and at higher resolution (1.98 Å) than the previous systematic specific damage study on a protein–DNA complex. Specific damage manifestations were determined within the largetrpRNA-binding attenuation protein (TRAP) bound to a single-stranded RNA that forms a belt around the protein. Over a large dose range, the RNA was found to be far less susceptible to radiation-induced chemical changes than the protein. The availability of two TRAP molecules in the asymmetric unit, of which only one contained bound RNA, allowed a controlled investigation into the exact role of RNA binding in protein specific damage susceptibility. The 11-fold symmetry within each TRAP ring permitted statistically significant analysis of the Glu and Asp damage patterns, with RNA binding unexpectedly being observed to protect these otherwise highly sensitive residues within the 11 RNA-binding pockets distributed around the outside of the protein molecule. Additionally, the method enabled a quantification of the reduction in radiation-induced Lys and Phe disordering upon RNA binding directly from the electron density.

Stimulated release of fluorescently labeled IgE fragments that efficiently accumulate in secretory granules after endocytosis in RBL-2H3 mast cells

1998 ◽  
Vol 111 (16) ◽  
pp. 2385-2396 ◽  
Author(s):  
K. Xu ◽  
R.M. Williams ◽  
D. Holowka ◽  
B. Baird
Keyword(s):  
Mast Cells ◽  
Fluorescence Microscopy ◽  
High Efficiency ◽  
Immunoglobulin E ◽  
Secretory Granules ◽  
Dose Dependence ◽  
Secretory Vesicles ◽  
Release Process ◽  
Intracellular Compartments ◽  
Stimulation Of

Sensitization of RBL-2H3 mast cells with monomeric fluorescein-5-isothiocyanate (FITC)-labeled immunoglobulin E (IgE) results in slow but highly efficient accumulation of labeled IgE fragments in a pool of acidic peripheral vesicles that are visible by fluorescence microscopy after raising endosomal pH with ammonium chloride. Stimulation of cells containing these FITC-IgE fragments by aggregation of high affinity receptors for IgE (FcepsilonRI) or by Ca2+ ionophore and phorbol 12-myristate 13-acetate results in release of FITC fluorescence from the cells, which can be monitored continuously with a spectrofluorometer. The fluorescence release process corresponds to cellular degranulation: it is prevented under conditions that prevent stimulated beta-hexosaminidase release, and these two processes exhibit the same antigen dose-dependence and kinetics. Pulse-chase labeling reveals that aggregation of FITC-IgE bound to FcepsilonRI at the cell surface causes internalization and delivery to the regulated secretory vesicles with a high efficiency similar to monomeric IgE-FcepsilonRI, but more rapidly. Binding of Cy3-modified IgE to FcepsilonRI results in labeling of the same secretory vesicles as in FITC-IgE-sensitized cells, and these Cy3-labeled vesicles can be observed by fluorescence microscopy without neutralization of intracellular compartments. Simultaneous three-photon microscopy of serotonin fluorescence and two-photon microscopy of Cy3 fluorescence reveals that these Cy3-labeled vesicles coincide with serotonin-labeled secretory granules. After stimulation of the cells via aggregation of IgE-FcepsilonRI or addition of Ca2+ ionophore and phorbol 12-myristate 13-acetate, depletion of the Cy3 label from the intracellular vesicles is observed with confocal microscopy. These results provide strong evidence for the lysosomal nature of secretory granules in these cells. In addition, they provide the basis for a direct, real-time method for monitoring single cell degranulation.

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