scholarly journals Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1465
Author(s):  
Jan Franc ◽  
Václav Dědič ◽  
Pavel Moravec ◽  
Martin Rejhon ◽  
Roman Grill ◽  
...  
Keyword(s):  
Space Charge ◽  
Spectral Dependence ◽  
Abrupt Change ◽  
Vickers Microhardness ◽  
Pockels Effect ◽  
Physical Explanation ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Photoplastic Effect ◽  
Illuminating Light

We studied the spectral dependence of the Vickers microhardness HV0.025 of CdZnTe and CdZnTeSe samples upon illumination and found out that it increases over the entire applied spectral range of 1540–750 nm. We also found out that the photoconductivity and microhardness are correlated. We observed changes in the correlation diagram (change of slope and an abrupt change of HV0.025 at several wavelengths of the illuminating light). Based on measurements of the relative changes of the space charge upon illumination using the Pockels effect, we suggest that the observed spectral dependence of positive photoplastic effect in CdZnTe and CdZnTeSe can be explained by the trapping of photoinduced electrons and holes, which affects the motion of the partial dislocations. The underlying physical explanation relies on the assumption that reconstructed bonds break before dislocation glide.

Structure of stacking faults in pyrite using TEM techniques

1992 ◽  
Vol 50 (1) ◽  
pp. 358-359
Author(s):  
Raja Subramanian ◽  
Kenneth S. Vecchio
Keyword(s):  
Lattice Structure ◽  
Stacking Faults ◽  
Covalent Bond ◽  
Group Symmetry ◽  
Iron Pyrite ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Contrast Analysis ◽  
Chlorine Ions

The structure of stacking faults and partial dislocations in iron pyrite (FeS2) have been studied using transmission electron microscopy. Pyrite has the NaCl structure in which the sodium ions are replaced by iron and chlorine ions by covalently-bonded pairs of sulfur ions. These sulfur pairs are oriented along the <111> direction. This covalent bond between sulfur atoms is the strongest bond in pyrite with Pa3 space group symmetry. These sulfur pairs are believed to move as a whole during dislocation glide. The lattice structure across these stacking faults is of interest as the presence of these stacking faults has been preliminarily linked to a higher sulfur reactivity in pyrite. Conventional TEM contrast analysis and high resolution lattice imaging of the faulted area in the TEM specimen has been carried out.

Molecular Dynamics studies of Dislocations in SI

1989 ◽  
Vol 163 ◽  
Author(s):  
M.S. Duesbery ◽  
D.J. Michel ◽  
B. Joos
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Partial Dislocation ◽  
Silicon Lattice ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Shear Strains ◽  
Free Environment

AbstractThe mobility of dislocations in a model Silicon lattice is examined at an atomistic level using molecular dynamics. Straight and double-kinked 30° and 90° partial dislocation glide-set dipoles are modelled in a strain-free environment: reconstruction and antiphase defects are found to be present for 30° partial dislocations. The effects of applied shear strains and of temperatures up to the melting point are considered.

Photoplastic effect and Vickers microhardness in III–V and II–VI semiconductor compounds

1997 ◽  
Vol 234-236 ◽  
pp. 865-868 ◽  
Author(s):  
S. Koubaiti ◽  
J.J. Couderc ◽  
C. Levade ◽  
G. Vanderschaeve
Keyword(s):  
Vickers Microhardness ◽  
Semiconductor Compounds ◽  
Photoplastic Effect

Photoplastic Effects in II-VI Crystals

1982 ◽  
Vol 14 ◽  
Author(s):  
Shin Takeuchi ◽  
Koji Maeda ◽  
Kiyokazu Nakagawa
Keyword(s):  
Free Path ◽  
Mean Free Path ◽  
In Situ Tem ◽  
Dislocation Loops ◽  
Microscopic Mechanism ◽  
Dislocation Glide ◽  
Illumination System ◽  
Work Hardening Rate ◽  
Photoplastic Effect ◽  
Semiconducting Compounds

ABSTRACTA reversible change in the flow stress with the illumination of a band gap light (photoplastic effect: PPE) is observed commonly in II-VI semiconducting compounds both with the zincblende and the wurtzite structures. After reviewing the experimental results accumulated so far concerning the usually observed PPE, detailed microscopic experiments on CdTe (partly on CdS) single crystals are described. In-situ TEM straining experiments with a laser illumination system clarified that the dislocation mobility, evidently controlled by the Peierls mechanism, is not affected by light illumination.The investigation of the dislocation glide behavior over a longer range using the etch pit method and the cathodoluminescence microscopy with a SEM revealed that the dislocations are apt to become immobilized after traveling a certain distance from the sources with a high velocity.The dislocation loops and cusps observed by TEM suggest that the immobilization is caused by jog formation along screw segments. Those results suggest that the positive PPE is caused by the decrease in the mean free path of multiplied dislocations due to the enhanced jog formation by illumination. This viewpoint is supported by the high density of dislocation debris left in specimens deformed under illumination, the enhanced work hardening rate under illumination and the reduction of the PPE when the dislocation mean free path becomes determined by other photoinsensitive factors such as forest dislocation cutting and specimen size. The microscopic mechanism of the enhanced jog formation is discussed in terms of electrostatic interaction between charged point defects and dislocation charge which is increased with the illumination.

Photoluminescence Study of the Driving Force for Stacking Fault Expansion in 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 395-398 ◽  
Author(s):  
Rii Hirano ◽  
Yuki Sato ◽  
Michio Tajima ◽  
Kohei M. Itoh ◽  
Koji Maeda
Keyword(s):  
Driving Force ◽  
Stacking Faults ◽  
Excitation Intensity ◽  
Band Edge Emission ◽  
Edge Emission ◽  
Sign Reversal ◽  
Laser Illumination ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Lattice Heating

We investigated expansion velocities of Shockley stacking faults (SSFs) in 4H-silicon carbide under laser illumination using photoluminescence methods. The experiments showed that the velocity of SSF expansion or the glide velocity of SSF-bounding 30°-Si(g) partial dislocations (PD) is supralinearly dependent on the excitation intensity. We estimated sample temperature by analyzing the broadening of band-edge emission and concluded that the lattice heating by laser illumination is not the cause of the enhanced dislocation glide. The supralinear dependence can be accounted for by a photo-induced sign reversal of the effective formation energy of SSF acting as the driving force of SSF expansion under the illumination.

Interaction between Recombination Enhanced Dislocation Glide Process Activated Basal Stacking Faults and Threading Dislocations in 4H-Silicon Carbide Epitaxial Layers

2007 ◽  
Vol 994 ◽  
Author(s):  
Yi Chen ◽  
Michael Dudley ◽  
Kendrick X Liu ◽  
Robert E Stahlbush
Keyword(s):  
Silicon Carbide ◽  
Partial Dislocation ◽  
Displacement Vector ◽  
Stacking Faults ◽  
Epitaxial Layers ◽  
Threading Dislocations ◽  
Screw Dislocations ◽  
Dislocation Glide ◽  
Shockley Partial ◽  
Partial Dislocations

AbstractElectron-hole recombination enhanced glide of Shockley partial dislocations bounding expanding stacking faults and their interactions with threading dislocations in 4H silicon carbide epitaxial layers have been studied using synchrotron white beam X-ray topography and in situ electroluminescence. The mobile silicon-core Shockley partial dislocations bounding the stacking faults are able to cut through threading edge dislocations leaving no trailing dislocation segments in their wake. However, when the Shockley partial dislocations interact with threading screw dislocations, trailing 30o partial dislocation dipoles are initially deposited in their wake due to the pinning effect of the threading screw dislocations. These dipoles spontaneously snap into their screw orientation, regardless the normally immobile carbon-core Shockley partial dislocation components in the dipoles. They subsequently cross slip and annihilate, leaving a prismatic stacking fault in (2-1-10) plane with the displacement vector 1/3[01-10].

Controlling Planar Defects in 3C-SiC: Ways to Wake it up as a Practical Semiconductor

2015 ◽  
Vol 821-823 ◽  
pp. 108-114 ◽  
Author(s):  
Hiroyoki Nagasawa ◽  
Ramya Gurunathan ◽  
Maki Suemitsu
Keyword(s):  
Phase Boundary ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Planar Defects ◽  
Forest Dislocation ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Blocking Property ◽  
Trapezoidal Plate ◽  
Anti Phase Boundary

Eelectrically active defects in 3C–SiC are investigated by considering the structures and interactions of planar defects. An anti-phase boundary (APB) largely degrades the blocking property of semiconductor devices due to its semimetallic nature. Although APBs can be eliminated by orienting the specific polar face of 3C-SiC along a particular direction, stacking faults (SFs) cannot be eliminated due to Shockley-type partial dislocation glide. SFs with Shockley-type partial dislocations form a trapezoidal plate which expands the Si-terminated surface with increasing 3C-SiC thickness. Although the density of SFs can be reduced by counter termination, specific cross-junctions between a pair of counter SFs forms a forest dislocation, and this is regarded as an electrically active defect. This paper proposes an effective way to suppress the forest dislocations and APBs which nucleate during 3C-SiC growth.

Separation of the Driving Force and Radiation-Enhanced Dislocation Glide in 4H-SiC

2012 ◽  
Vol 725 ◽  
pp. 35-40 ◽  
Author(s):  
Koji Maeda ◽  
Rii Hirano ◽  
Yuki Sato ◽  
Michio Tajima
Keyword(s):  
Driving Force ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Dislocation Velocity ◽  
Electronic Excitations ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Simultaneous Measurements ◽  
Pl Mapping ◽  
Anomalous Expansion

Anomalous expansion of stacking faults (SFs) induced in 4H-SiC under electronic excitations is driven by an electronic force and is achieved by enhanced glide of partial dislocations. An experimental attempt to separate the two physically different effects has been made by conducting photoluminescence (PL) mapping experiments which allowed simultaneous measurements of partial dislocation velocity and SF-originated PL intensity the latter of which is proposed to be related to the driving force for SF expansion through the density of free excitons planarly confined in the SF.

Theory of Dislocations in SiC: The Effect of Charge on Kink Migration

2006 ◽  
Vol 527-529 ◽  
pp. 321-326
Author(s):  
T.A.G. Eberlein ◽  
R. Jones ◽  
A.T. Blumenau
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Forward Bias ◽  
Compound Semiconductors ◽  
Stacking Fault ◽  
Computing Power ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Fault Growth ◽  
Atomic And Electronic Structure

Under forward bias bipolar 4H- and 6H-SiC devices are known to degrade rapidly through stacking fault formation and expansion in the basal plane. It is believed that the ob- served rapid stacking fault growth is due to a recombination-enhanced dislocation glide (REDG) mechanism at the bordering partial dislocations. This degradation phenomenon has generated considerable interest in the involved dislocations — in particular in their atomic and electronic structure, but also in the mechanisms of their glide motion. Fortunately, nowadays advances in computing power and in theoretical methodology allow the ab initio based modelling of some aspects of the problem. This paper therefore gives a brief review of recent activities in this field, and further discusses some general problems of ab initio based modelling of dislocations in compound semiconductors.

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