Evidence for Different Kinds of Dangling Bond Defects in a-Si:H

1993 ◽  
Vol 297 ◽  
Author(s):  
Minh Tran ◽  
H. Fritzsche ◽  
P. Stradins
Keyword(s):  
Defect Concentration ◽  
Electron Lifetime ◽  
Native Defect ◽  
Dangling Bond ◽  
Native Defects

Comparing the photoconductivity σp of undoped samples with different native defect concentrations we find that light-induced metastable defects decrease the electron lifetime more strongly than the native defects. We discuss the differences between native and metastable dangling bond defects. We find that the constant photocurrent method underestimates the defect concentration in undoped a-Si:H.

Nature of the native-defect ESR and hydrogen-dangling-bond centers in thin diamond films

1993 ◽  
Vol 48 (23) ◽  
pp. 17595-17598 ◽  
Author(s):  
H. Jia ◽  
J. Shinar ◽  
D. P. Lang ◽  
M. Pruski
Keyword(s):  
Diamond Films ◽  
Native Defect ◽  
Dangling Bond

On the Nature of the Native Defect ESR in Thin Diamond Films

1994 ◽  
Vol 339 ◽  
Author(s):  
J. Shinar ◽  
H. Jia ◽  
D. P. Lang ◽  
M. Pruski
Keyword(s):  
Relaxation Rate ◽  
Diamond Films ◽  
Stacking Faults ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Native Defect ◽  
Paramagnetic Centers ◽  
Dangling Bond ◽  
Spin Lattice ◽  
X Band

ABSTRACTThe X-band ESR of thin diamond films deposited from 99.5% H2/0.5% CH4 is compared to that of films similarly prepared from D2CD4 and H2/13CH4. The main line and the satellites at ±7.2 G are unaffected by annealing at T <. 1100°C, but their intensity is reduced upon annealing at T ∼ 1200°C. As the satellites are absent from the deuterated films, they are attributed to newly identified dangling bond-H centers, either on internal microvoid surfaces or embedded in the tetrahedral network. This is consistent with the 13C spin-lattice relaxation rate, which indicates that the distribution of paramagnetic centers is homogeneous to within ∼0.04 μm. However, they may be nonuniformly distributed on a finer scale, consistent with the concentrations in m ulti vacancies or stacking faults recently suggested by Fanciulli and Moustakas.

scholarly journals Native Umbilical Defect for Laparoscopic Entry

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
Tarek Osama Hegazy ◽  
Mohamed Hassan Ali ◽  
Ahmed Amr Mohsen ◽  
Mahmoud Azhary ◽  
Ahmad Yahia Abdel Dayem
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Native Defect ◽  
Open Technique ◽  
Entry Site ◽  
Native Defects ◽  
Umbilical Incision ◽  
Trocar Insertion ◽  
Laparoscopic Entry ◽  
Direct Trocar Insertion

Background: The presence of defects in native umbilical in adults and its use as laparoscopic first entry site is poorly documented. It would likely be a safer method than the Veress needle and direct trocar insertion. This work aimed to report the prevalence and size of native umbilical defects, and their relationship with gender, age and body mass index. Methods: In 160 consecutive laparoscopic operations, a trans-umbilical incision was made and a defect at its base was looked for. When found, the defect was measured and used as the first port entry site. Relationships of presence of native defects and their sizes in relation to gender, age and BMI were analyzed. Results: The prevalence of a native defect in this series was 90%. Its presence had no relation with gender, age or BMI. Its size, however, positively correlated with age and BMI. No complications were related to the defect’s use for first laparoscopic entry site. Conclusion: A native umbilical defect is present in 90% of adults. Whenever present, it is recommended for use as the first port entry site by an open technique. This method is simple and safe and avoids unnecessarily inducing another defect. Keywords: Laparoscopy, Open technique, Access, Native defect, Umbilical defect

scholarly journals Native defect-assisted enhanced response to CH4 near room temperature by Al0.07Ga0.93N nanowires

2018 ◽  
Vol 20 (27) ◽  
pp. 18391-18399 ◽  
Author(s):  
Santanu Parida ◽  
A. Das ◽  
Arun K. Prasad ◽  
Jay Ghatak ◽  
Sandip Dhara
Keyword(s):  
Room Temperature ◽  
Native Defect ◽  
Native Defects

Enhanced CH4 sensing with sufficient sensitivity of 100 ppm at 50 °C is realized for Al0.07Ga0.93N nanowires by utilizing native defects.

On the Origin of the New Electron Traps Induced By Rapid Thermal Annealing in GaAs Using Capping Proximity Technique.

1988 ◽  
Vol 144 ◽  
Author(s):  
G. Marrakchi ◽  
G. Chaussemy ◽  
A. Laugier ◽  
G. Guillot.
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Native Defect ◽  
Physical Origin ◽  
Electron Traps ◽  
Native Defects ◽  
Growth Method ◽  
Transient Spectroscopy

ABSTRACTRapid Thermal Annealing (RTA) effects on generation or annihilation of deep levels in GaAs have been investigated by Deep Level Transient Spectroscopy (DLTS). Capping proximity technique using three annealing configurations are employed to anneal Liquid Encapsulated Czochralski (LEC) and Bridgman (B) substrates, or Vapor Phase Epitaxy (VPE) and Liquid Phase Epitaxy (LPE) layers. The RTA treatment is performed from 800 to 950°C for two annealing times ( 3 and 10s).The DLTS data show that the evolution of the native defects depends on the GaAs growth method and also the annealing configuration. We observe the appearance of two new electron traps named RL1 and RL2 induced by the RTA process which depend on the kind of substrate: RL1 and RL2 are created in LEC material while only RL1 is detected in B material. A general comparison of our results with others reported in the literature show that these new electron traps are related to the change of stoichiometry at the GaAs surface and also depend on the existence of specific native defects in the starting GaAs material. It is proposed that the creation of RL1 is related to the EL6 native defect and discuss a possible physical origin for this level. We also propose that RL2 and EL5 originate from the same defect and suggest the divacancy VGaVAs as a possible origin for this trap.

Photocarrier capture properties of light-induced defects in a-Si:H

2001 ◽  
Vol 664 ◽  
Author(s):  
Paul Stradins ◽  
Satoshi Shimizu ◽  
Michio Kondo ◽  
Akihisa Matsuda
Keyword(s):  
Light Exposure ◽  
Wide Distribution ◽  
Defect Concentration ◽  
Exposure Condition ◽  
Dangling Bond ◽  
Charge Balance ◽  
Effective Electron ◽  
Wide Range ◽  
Defect Creation ◽  
Induced Defects

ABSTRACTLight-induced degradation of photoconductive properties is investigated as a function of lightinduced Si dangling bond defect concentration and subgap absorption. This relation is studied for a variety of sample preparation techniques including a-Si:D, wide range of temperatures during light exposure and annealing, and sample degradation pre-history. Under a given exposure condition, light-induced defects have a fixed effective electron capture coefficient, while its value varies greatly with exposure conditions (temperature during exposure or stepwise anneal) and with sample microstructure. This explains commonly observed non-linear dependences and hysteresis between defect concentration and mobility-lifetime product. Creation efficiency of less-stable defects with large capture coefficients is not influenced by the presence of a large number of stable defects. Structural change accompanying the defect creation, if any, is strongly related to the defect creation and is likely to occur locally around the defects, modifying their capture coefficients. Capture can vary both because of the changes in intrinsic capture probabilities and due to changes in the net defect charge balance. The former may be increased by the presence of H or photocarrier trap (e.g. weak bond tail state) in a close vicinity of Si dangling bond. The latter may be caused by a wide distribution of defect states in the gap or by simultaneous creation of negatively charged floating bond states near VB edge.

NATIVE DEFECT COMPENSATION IN III-ANTIMONIDE BULK SUBSTRATES

2004 ◽  
Vol 14 (03) ◽  
pp. 658-663 ◽  
Author(s):  
ROBINSON PINO ◽  
YOUNGOK KO ◽  
PARTHA S. DUTTA
Keyword(s):  
Low Temperature ◽  
Carrier Concentration ◽  
Carrier Density ◽  
Native Defect ◽  
High Concentration ◽  
Temperature Growth ◽  
Native Defects ◽  
Low Temperature Growth ◽  
Order Of Magnitude ◽  
Impurity Doping

As-grown, undoped III-antimonide bulk substrates contain high concentration of native defects resulting in high residual carrier density. In this paper, we have demonstrated that native defects can be compensated in bulk substrates of GaSb , InSb , and Ga 1-x In x Sb via impurity doping and low temperature growth from nonstoichiometric melts and solutions. Decrease in residual carrier concentration up to one order of magnitude at 300 K and three orders of magnitude at 77 K have been achieved.

Theoretical Investigation of Nitrogen-Doping Effect on Native Defect Aggregation Processes in Silicon

2002 ◽  
Vol 719 ◽  
Author(s):  
H. Kageshima ◽  
A. Taguchi ◽  
K. Wada
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Nitrogen Doping ◽  
Doping Effect ◽  
Native Defect ◽  
First Principles Calculations ◽  
Native Defects ◽  
Aggregation Processes ◽  
Defect Aggregation ◽  
Shed Light

AbstractWe theoretically investigated interactions between nitrogen (N) atoms and Si native defects, vacancy (V) and interstitial (I), by using first-principles calculations in order to shed light on the nitrogen-doping effect on the defect aggregation processes. Stabilities of various N-I and N-V complexes are examined by calculating the total energy. We found that N atoms form stable complexes with both of V and I. The formation of such stable complexes reduces the effective concentrations of the native defects, resulting in the suppression of aggregation processes of V and I.

Optical and Electrical Characterizations of AlxGa1−xSb

1987 ◽  
Vol 94 ◽  
Author(s):  
N. Kitamura ◽  
H. Yamamoto ◽  
K. Higuchi ◽  
Y. Maeda ◽  
A. Usami ◽  
...  
Keyword(s):  
Stoichiometric Composition ◽  
Acceptor Level ◽  
Native Defect ◽  
Shallow Acceptor ◽  
Native Defects ◽  
Complex Defect ◽  
Shallow Acceptor Level ◽  
Epma Measurement ◽  
Defect Levels ◽  
Electrical Characterizations

ABSTRACTThe LPE grown AlxGa1−xSb was investigated by means of TEM, a carrier profiler and PL. The TEM image showed the dissociated 60° dislocations and Lomer-Cottrell sessile dislocation formed by the reaction of two dissociated 60° dislocations on different {111} planes. The EPMA measurement showed that Sb concentrations at the dislocation were lower than the stoichiometric composition. The epi-layer grown at 400°C had a relatively uniform carrier concentration of ∼7×1016cm−3. The PL spectra showed five emission peaks in 0≦×≦0.29. One shallow acceptor level and two native defect levels were introduced to interpret these PL emissions. The shallow acceptor level of Ev+∼30meV may be due to the defect of VGaGaSb. The native defects introduce two levels of EΓ1 - ∼90meV and EL1 - ∼160meV. The defect levels may be related to the complex defect of the Sb vacancy.

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