Evaluation and Control of Plastic Deformation in GaAs Film on Si Substrate by Means of Crystal Plasticity Analysis

1992 ◽  
Vol 280 ◽  
Author(s):  
Tetsuya Ohashi
Keyword(s):  
Plastic Deformation ◽  
Continuum Mechanics ◽  
Crystal Plasticity ◽  
Silicon Substrate ◽  
Room Temperature ◽  
Surface Region ◽  
Gaas Film ◽  
Si Substrate ◽  
New Approach ◽  
And Control

ABSTRACTDislocation accumulation in patterned gallium-arsenide film, which is deposited on silicon substrate and cooled down from the deposition to room temperature, is numerically simulated under a continuum mechanics approximation. A new approach to suppression of dislocation accumulation is proposed where selective growth of the film and partial doping of impurities into it are combined. The results show the possibility to keep the surface region of the film almost dislocation free.

Suppression of dislocation accumulation in GaAs film on Si substrate by combination of impurity doping and selective area growth

1992 ◽  
Vol 7 (11) ◽  
pp. 3032-3038 ◽  
Author(s):  
Tetsuya Ohashi
Keyword(s):  
Room Temperature ◽  
Surface Region ◽  
Selective Area Growth ◽  
Gaas Film ◽  
Grown Film ◽  
Si Substrate ◽  
New Approach ◽  
Selective Area ◽  
Impurity Doping ◽  
Film Substrate

Dislocation accumulation in gallium-arsenide film, which is deposited on silicon substrate and cooled down from the deposition to room temperature, is examined by crystal plasticity simulation. A new approach to suppression of dislocation accumulation is proposed such that selective growth of the film and partial doping of impurities into it are combined. The results show the possibility to localize the plastic deformation near the film/substrate interface and to keep the surface region of the film almost dislocation-free. Geometry of the selectively grown film and a strategy for partial doping of impurities, which suppresses the dislocation accumulation in the surface region of the film, are considered.

Investigation of irradiation-induced nucleation processes in silicon and germanium

1995 ◽  
Vol 53 ◽  
pp. 224-225
Author(s):  
Harry A. Atwater ◽  
C.M. Yang ◽  
K.V. Shcheglov
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Initial Distribution ◽  
Engineering Control ◽  
Size Evolution ◽  
Silicon And Germanium ◽  
Ge Quantum Dot ◽  
And Control ◽  
Germanium Quantum Dots ◽  
Kinetics Of

Studies of the initial stages of nucleation of silicon and germanium have yielded insights that point the way to achievement of engineering control over crystal size evolution at the nanometer scale. In addition to their importance in understanding fundamental issues in nucleation, these studies are relevant to efforts to (i) control the size distributions of silicon and germanium “quantum dots𠇍, which will in turn enable control of the optical properties of these materials, (ii) and control the kinetics of crystallization of amorphous silicon and germanium films on amorphous insulating substrates so as to, e.g., produce crystalline grains of essentially arbitrary size.Ge quantum dot nanocrystals with average sizes between 2 nm and 9 nm were formed by room temperature ion implantation into SiO2, followed by precipitation during thermal anneals at temperatures between 30°C and 1200°C[1]. Surprisingly, it was found that Ge nanocrystal nucleation occurs at room temperature as shown in Fig. 1, and that subsequent microstructural evolution occurred via coarsening of the initial distribution.

A crystallographic analysis of the CoSi/Si(111) interface using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 574-575
Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Room Temperature ◽  
Theoretical Method ◽  
Crystallographic Analysis ◽  
Si Substrate ◽  
Transmission Electron ◽  
Theoretical Predictions

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

On-Surface Radical Oligomerisation: A New Approach to STM Tip-Induced Reactions

2018 ◽  
Author(s):  
Gaolei Zhan ◽  
Younes Makoudi ◽  
Judicael Jeannoutot ◽  
Simon Lamare ◽  
Michel Féron ◽  
...  
Keyword(s):  
Sample Surface ◽  
Scanning Tunnelling Microscope ◽  
Transfer Event ◽  
New Approach ◽  
The Past ◽  
Organic Nanostructures ◽  
Scanning Tunnelling ◽  
New Strategy ◽  
Surface Fabrication ◽  
And Control

Over the past decade, on-surface fabrication of organic nanostructures has been widely investigated for the development of molecular electronic devices, nanomachines, and new materials. Here, we introduce a new strategy to obtain alkyl oligomers in a controlled manner using on-surface radical oligomerisations that are triggered by the electrons/holes between the sample surface and the tip of a scanning tunnelling microscope. The resulting radical-mediated mechanism is substantiated by a detailed theoretical study. This electron transfer event only occurs when <i>V</i><sub>s</sub> < -3 V or <i>V</i><sub>s</sub> > + 3 V and allows access to reactive radical species under exceptionally mild conditions. This transfer can effectively ‘switch on’ a sequence leading to formation of oligomers of defined size distribution due to the on-surface confinement of reactive species. Our approach enables new ways to initiate and control radical oligomerisations with tunnelling electrons, leading to molecularly precise nanofabrication.

scholarly journals Thermochromic aggregation-induced dual phosphorescence via temperature-dependent sp3-linked donor-acceptor electronic coupling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tao Wang ◽  
Zhubin Hu ◽  
Xiancheng Nie ◽  
Linkun Huang ◽  
Miao Hui ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Electronic Coupling ◽  
Temperature Dependent ◽  
Molecular Systems ◽  
Donor And Acceptor ◽  
Theoretical Investigations ◽  
Donor Acceptor ◽  
And Control ◽  
Two Temperature

AbstractAggregation-induced emission (AIE) has proven to be a viable strategy to achieve highly efficient room temperature phosphorescence (RTP) in bulk by restricting molecular motions. Here, we show that by utilizing triphenylamine (TPA) as an electronic donor that connects to an acceptor via an sp3 linker, six TPA-based AIE-active RTP luminophores were obtained. Distinct dual phosphorescence bands emitting from largely localized donor and acceptor triplet emitting states could be recorded at lowered temperatures; at room temperature, only a merged RTP band is present. Theoretical investigations reveal that the two temperature-dependent phosphorescence bands both originate from local/global minima from the lowest triplet excited state (T1). The reported molecular construct serves as an intermediary case between a fully conjugated donor-acceptor system and a donor/acceptor binary mix, which may provide important clues on the design and control of high-freedom molecular systems with complex excited-state dynamics.

scholarly journals Normal cells repel WWOX-negative or -dysfunctional cancer cells via WWOX cell surface epitope 286-299

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yu-An Chen ◽  
Yong-Da Sie ◽  
Tsung-Yun Liu ◽  
Hsiang-Ling Kuo ◽  
Pei-Yi Chou ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cancer Cells ◽  
Room Temperature ◽  
Metastatic Cancer ◽  
Normal Cells ◽  
Tgfβ Receptor ◽  
Membrane Type ◽  
Cell Invasiveness ◽  
And Control ◽  
Metastatic Cancer Cells

AbstractMetastatic cancer cells are frequently deficient in WWOX protein or express dysfunctional WWOX (designated WWOXd). Here, we determined that functional WWOX-expressing (WWOXf) cells migrate collectively and expel the individually migrating WWOXd cells. For return, WWOXd cells induces apoptosis of WWOXf cells from a remote distance. Survival of WWOXd from the cell-to-cell encounter is due to activation of the survival IκBα/ERK/WWOX signaling. Mechanistically, cell surface epitope WWOX286-299 (repl) in WWOXf repels the invading WWOXd to undergo retrograde migration. However, when epitope WWOX7-21 (gre) is exposed, WWOXf greets WWOXd to migrate forward for merge. WWOX binds membrane type II TGFβ receptor (TβRII), and TβRII IgG-pretreated WWOXf greet WWOXd to migrate forward and merge with each other. In contrast, TβRII IgG-pretreated WWOXd loses recognition by WWOXf, and WWOXf mediates apoptosis of WWOXd. The observatons suggest that normal cells can be activated to attack metastatic cancer cells. WWOXd cells are less efficient in generating Ca2+ influx and undergo non-apoptotic explosion in response to UV irradiation in room temperature. WWOXf cells exhibit bubbling cell death and Ca2+ influx effectively caused by UV or apoptotic stress. Together, membrane WWOX/TβRII complex is needed for cell-to-cell recognition, maintaining the efficacy of Ca2+ influx, and control of cell invasiveness.

A comparative study of plastic deformation mechanisms in room-temperature and cryogenically deformed magnesium alloy AZ31

2021 ◽  
Vol 807 ◽  
pp. 140821
Author(s):  
Kai Zhang ◽  
Zhutao Shao ◽  
Christopher S. Daniel ◽  
Mark Turski ◽  
Catalin Pruncu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Magnesium Alloy ◽  
Comparative Study ◽  
Room Temperature ◽  
Deformation Mechanisms ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

Sign in / Sign up

Export Citation Format

Share Document