Bulk Defects and Radiation Damage in Detector Grade Silicon

1993 ◽  
Vol 302 ◽  
Author(s):  
J. Walter ◽  
W. Garber ◽  
R. Wunstorf ◽  
W. Bugg ◽  
J. Harvey ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Point Defects ◽  
Deep Level ◽  
Radiation Detectors ◽  
Impurity Density ◽  
Neutron Damage ◽  
Current State ◽  
Neutron Transmutation ◽  
Grade Silicon ◽  
Induced Changes

ABSTRACTThe importance of bulk defects in Si to the performance of Si radiation detectors is discussed and the current state of knowledge about deep level defects, including those induced by radiation damage, is briefly reviewed. The importance and origins of the fluctuations in the spatial distribution of the shallow point defects which determine the uncompensated net impurity density are discussed and information on this problem in FZ silicon, multipass FZ silicon, neutron transmutation doped Si, and radiation damaged Si is presented and compared to what should be expected on the basis of simple modeling. A new model for radiation damage induced changes in the net uncompensated impurity density is reviewed and compared to experimental data on fast neutron damage in Si.

Molecular Dynamics Simulation of Neutron Damage in β-SIC

1998 ◽  
Vol 540 ◽  
Author(s):  
J.M. Perlado ◽  
L. Malerba ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Point Defects ◽  
Damage Accumulation ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Temperature Sensitive ◽  
Neutron Damage ◽  
Preliminary Study ◽  
Threshold Displacement

AbstractMolecular Dynamics (MD) simulations of neutron damage in β-SiC have been performed using a modified version of the Tersoff potential. The Threshold Displacement Energy (TDE) for Si and C atoms at 300 K has been determined along directions [001], [110], [111] and [ 1 1 1 ]. The existence of recombination barriers, which allow the formation of metastable, temperature-sensitive defects even below the threshold, has been observed. Displacement cascades produced by both C- and Si-recoils of energies spanning from 0.5 keV up to, respectively, 5 keV and 8 keV have also been simulated at 300 K and 1300 K. Their analysis, together with the analysis of damage accumulation (∼3.4×10-3 DPA) at 1300 K, reveals that the two sub-lattices exhibit opposite responses to irradiation: whereas only a little damage is produced on the “ductile” Si sub-lattice, many point-defects accumulate on the much more “fragile” C sub-lattice. A preliminary study of the nature and clustering tendency of these defects is performed. The possibility of disorder-induced amorphization is considered and the preliminary result is that no amorphization takes place at the dose and temperature simulated.

Displacement cascade evolution in tungsten with pre-existing helium and hydrogen clusters: a molecular dynamics study

2020 ◽  
Vol 111 (8) ◽  
pp. 698-705
Author(s):  
Mohammad Abu-Shams ◽  
Jeffery Moran ◽  
Ishraq Shabib
Keyword(s):  
Molecular Dynamics ◽  
Point Defect ◽  
Radiation Damage ◽  
Point Defects ◽  
High Energy ◽  
Dynamics Simulation ◽  
Power Relationship ◽  
Hydrogen Clusters ◽  
Displacement Cascades ◽  
Hydrogen Defects

Abstract The effects of radiation damage on bcc tungsten with preexisting helium and hydrogen clusters have been investigated in a high-energy environment via a comprehensive molecular dynamics simulation study. This research determines the interactions of displacement cascades with helium and hydrogen clusters integrated into a tungsten crystal generating point defect statistics. Helium or hydrogen clusters of atoms~0.1% of the total number of atoms have been randomly distributed within the simulation model and primary knock-on-atom (PKA) energies of 2.5, 5, 7.5 and 10 keV have been used to generate displacement cascades. The simulations quantify the extent of radiation damage during a simulated irradiation cycle using the Wigner-Seitz point defect identification technique. The generated point defects in crystals with and without pre-existing helium/hydrogen defects exhibit a power relationship with applied PKA energy. The point defects are classified by their atom type, defect type, and distribution within the irradiated model. The presence of pre-existing helium and hydrogen clusters significantly increases the defects (5 - 15 times versus pure tungsten models). The vacancy composition is primarily tungsten (e. g., ~70% at 2.5 keV) in models with pre-existing helium, but the interstitials are primarily He (e. g., ~89% at 10 keV). On the other hand, models with pre-existing hydrogen have a vacancy composition that is primarily tungsten (more than 90% irrespective of PKA energy), and the interstitial composition is more balanced between tungsten (average 46%) and hydrogen (average 54%) interstitials across the PKA range. The distribution of the atoms reveals that the tungsten point defects prefer to reside close to the position of cascade initiation, but helium or hydrogen defects reside close to the positions where clusters are built.

Neutron Damage in SiC Semiconductor Radiation Detectors in the GT-MHR

2009 ◽  
pp. 459-459-8
Author(s):  
T. E. Blue ◽  
B. Lohan ◽  
B. Khorsandi ◽  
D. W. Miller
Keyword(s):  
Radiation Detectors ◽  
Neutron Damage

Hyperfine and Superhyperfine Tensors as Probes of the Local Environment of Deep-Level Defect Centers

1990 ◽  
Vol 209 ◽  
Author(s):  
Michael Cook ◽  
C.T. White
Keyword(s):  
Point Defects ◽  
Deep Level ◽  
Local Environment ◽  
Solid Material ◽  
Crystalline Lattice ◽  
Deep Level Defect ◽  
Defect Centers ◽  
Amorphous Network

Point defects occur in every solid material. No crystalline lattice is perfect, and no amorphous network has only unbroken sequences of bonds. Every material contains a greater or smaller number of vacancies, interstitials, substitutional atoms, and broken bonds. Many of these have only minor effects on the behavior of the material, but in a surprisingly large number of cases, point defects can have significant and even decisive effects on material performance. This can be true even when the defects are present in very small concentrations.

Electron Radiation Damage and Properties of Point Defects in Molybdenum

1976 ◽  
Vol 41 (5) ◽  
pp. 1575-1583 ◽  
Author(s):  
Michio Kiritani ◽  
Yasuhiro Maehara ◽  
Hiroshi Takata
Keyword(s):  
Radiation Damage ◽  
Point Defects ◽  
Electron Radiation

Evolution of Charged Gap Statesin a- Si:H Under Light Exposure

2003 ◽  
Vol 762 ◽  
Author(s):  
M. Zeman ◽  
V. Nádaždy ◽  
R.A.C.M.M. van Swaaij ◽  
R. Durný ◽  
J.W. Metselaar
Keyword(s):  
Deep Level ◽  
Light Exposure ◽  
Dark Conductivity ◽  
Initial Energy ◽  
Energy Distributions ◽  
Transient Spectroscopy ◽  
Induced Changes ◽  
Hydrogenated Amorphous ◽  
Kinetics Of ◽  
Positively Charged

AbstractThe charge deep-level transient spectroscopy (Q-DLTS) experiments on undoped hydrogenated amorphous silicon (a-Si:H) demonstrate that during light soaking the states in the upper part of the gap disappear, while additional states around and below midgap are created. Since no direct correlation is observed in light-induced changes of the three groups of states that we identify from the Q-DLTS signal, we believe that we deal with three different types of defects. Positively charged states above midgap are related to a complex formed by a hydrogen molecule and a dangling bond. Negatively charged states below midgap are attributed to floating bonds. Various trends in the evolution of dark conductivity due to light soaking indicate that the kinetics of light-induced changes of the three gap-state components depend on their initial energy distributions and on the spectrum and intensity of light during exposure.

Investigation of Deep Levels In X-Ray Detector Material With Photo Induced Current Transient Spectroscopy (Picts)

1993 ◽  
Vol 302 ◽  
Author(s):  
C Eiche ◽  
M Fiederle ◽  
J Weese ◽  
D Maier ◽  
D Ebling ◽  
...  
Keyword(s):  
Tikhonov Regularization ◽  
Deep Level ◽  
Great Influence ◽  
Simulated Data ◽  
Radiation Detectors ◽  
Deep Levels ◽  
High Resistivity ◽  
Pulse Excitation ◽  
Detector Performance ◽  
Transient Spectroscopy

ABSTRACTDeep levels have a great influence on the recombination behavior of the free carriers in semiconductors. For several years PICTS has been used to investigate the deep levels in high resistivity material such as GaAs or CdTe used in detector applications. An important feature of the PICTS measurements is the analysis of the current transients after pulse excitation. We propose using a new method based on Tikhonov regularization. This method was implemented in the program FTIKREG (Fast Tikhonov Regularization) by one of the authors. The superior resolution of the regularization method in comparison to conventional techniques is shown using simulated data. Moreover, the method is applied to investigate deep levels in CdTe:Cl, SI-GaAs and GaAs:Cr samples used for room temperature radiation detectors. A relation between deep level properties and detector performance is proposed.

scholarly journals Temperature-dependent macromolecular X-ray crystallography

2010 ◽  
Vol 66 (4) ◽  
pp. 437-446 ◽  
Author(s):  
Martin Weik ◽  
Jacques-Philippe Colletier
Keyword(s):  
Radiation Damage ◽  
Routine Data ◽  
Dynamical Behaviour ◽  
Biological Macromolecules ◽  
X Ray ◽  
X Ray Crystallography ◽  
Structural Details ◽  
Induced Changes ◽  
Structural Insights ◽  
Reaction Initiation

X-ray crystallography provides structural details of biological macromolecules. Whereas routine data are collected close to 100 K in order to mitigate radiation damage, more exotic temperature-controlled experiments in a broader temperature range from 15 K to room temperature can provide both dynamical and structural insights. Here, the dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. Experimental strategies of kinetic crystallography are discussed that have allowed the generation and trapping of macromolecular intermediate states by combining reaction initiation in the crystalline state with appropriate temperature profiles. A particular focus is on recruiting X-ray-induced changes for reaction initiation, thus unveiling useful aspects of radiation damage, which otherwise has to be minimized in macromolecular crystallography.

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