Competing thermal expansion mismatch and lattice strain engineered growth of crack free WS2 in-plane heterostructures

2018 ◽  
Vol 6 (42) ◽  
pp. 11407-11415 ◽  
Author(s):  
Pawan Kumar ◽  
Birender Singh ◽  
Pradeep Kumar ◽  
Viswanath Balakrishnan
Keyword(s):  
Thermal Expansion ◽  
Lattice Strain ◽  
Thermal Expansion Mismatch ◽  
Thermal Mismatch ◽  
Lattice Strains

Formation of heterophase WS2 cancels the competing thermal mismatch and lattice strains and stabilizes crack free monolayer heterostructures while homophase monolayer suffers from severe cracking.

Microstructural and Microchemical Characterization of Nickel Sulfide Inclusions in Plate Glass

1991 ◽  
Vol 49 ◽  
pp. 962-963
Author(s):  
J. Cooper ◽  
O. Popoola ◽  
W. M. Kriven
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Glass Matrix ◽  
Nickel Sulfide ◽  
Plate Glass ◽  
Thermal Expansion Mismatch ◽  
Volume Increase ◽  
Β Phase ◽  
Microchemical Characterization

Nickel sulfide inclusions have been implicated in the spontaneous fracture of large windows of tempered plate glass. Two alternative explanations for the fracture-initiating behaviour of these inclusions have been proposed: (1) the volume increase which accompanies the α to β phase transformation in stoichiometric NiS, and (2) the thermal expansion mismatch between the nickel sulfide phases and the glass matrix. The microstructure and microchemistry of the small inclusions (80 to 250 μm spheres), needed to determine the cause of fracture, have not been well characterized hitherto. The aim of this communication is to report a detailed TEM and EDS study of the inclusions.

scholarly journals Unravelling thermal stress due to thermal expansion mismatch in metal–organic frameworks for methane storage

2021 ◽  
Author(s):  
Jelle Wieme ◽  
Veronique Van Speybroeck
Keyword(s):  
Thermal Expansion ◽  
Thermal Stress ◽  
Pressure Coefficient ◽  
Metal Organic Frameworks ◽  
Methane Storage ◽  
Thermal Expansion Mismatch ◽  
Thermal Pressure ◽  
Temperature Changes ◽  
Metal Organic ◽  
The Impact

Thermal stress is present in metal–organic frameworks undergoing temperature changes during adsorption and desorption. We computed the thermal pressure coefficient as a proxy for this phenomenon and discuss the impact of thermal expansion mismatch.

New physically based model for thermal induced initial stress in 3D for silicon germanium films after deposition

2014 ◽  
Vol 33 (6) ◽  
pp. 2121-2138 ◽  
Author(s):  
Abderrazzak El Boukili
Keyword(s):  
Thermal Expansion ◽  
Initial Stress ◽  
Silicon Germanium ◽  
Rate Of Change ◽  
Thermal Mismatch ◽  
Electronic Band ◽  
Physically Based Model ◽  
Content Type ◽  
Physically Based ◽  
Pmos Transistor

Purpose – The purpose of this paper is to provide a new three dimension physically based model to calculate the initial stress in silicon germanium (SiGe) film due to thermal mismatch after deposition. We should note that there are many other sources of initial stress in SiGe films or in the substrate. Here, the author is focussing only on how to model the initial stress arising from thermal mismatch in SiGe film. The author uses this initial stress to calculate numerically the resulting extrinsic stress distribution in a nanoscale PMOS transistor. This extrinsic stress is used by industrials and manufacturers as Intel or IBM to boost the performances of the nanoscale PMOS and NMOS transistors. It is now admitted that compressive stress enhances the mobility of holes and tensile stress enhances the mobility of electrons in the channel. Design/methodology/approach – During thermal processing, thin film materials like polysilicon, silicon nitride, silicon dioxide, or SiGe expand or contract at different rates compared to the silicon substrate according to their thermal expansion coefficients. The author defines the thermal expansion coefficient as the rate of change of strain with respect to temperature. Findings – Several numerical experiments have been used for different temperatures ranging from 30 to 1,000°C. These experiments did show that the temperature affects strongly the extrinsic stress in the channel of a 45 nm PMOS transistor. On the other hand, the author has compared the extrinsic stress due to lattice mismatch with the extrinsic stress due to thermal mismatch. The author found that these two types of stress have the same order (see the numerical results on Figures 4 and 12). And, these are great findings for semiconductor industry. Practical implications – Front-end process induced extrinsic stress is used by manufacturers of nanoscale transistors as the new scaling vector for the 90 nm node technology and below. The extrinsic stress has the advantage of improving the performances of PMOSFETs and NMOSFETs transistors by enhancing mobility. This mobility enhancement fundamentally results from alteration of electronic band structure of silicon due to extrinsic stress. Then, the results are of great importance to manufacturers and industrials. The evidence is that these results show that the extrinsic stress in the channel depends also on the thermal mismatch between materials and not only on the material mismatch. Originality/value – The model the author is proposing to calculate the initial stress due to thermal mismatch is novel and original. The author validated the values of the initial stress with those obtained by experiments in Al-Bayati et al. (2005). Using the uniaxial stress generation technique of Intel (see Figure 2). Al-Bayati et al. (2005) found experimentally that for 17 percent germanium concentration, a compressive initial stress of 1.4 GPa is generated inside the SiGe layer.

Thermal mismatch strain induced disorder of Y2Mo3O12 and its effect on thermal expansion of Y2Mo3O12/Al composites

2017 ◽  
Vol 19 (19) ◽  
pp. 11778-11785 ◽  
Author(s):  
Chang Zhou ◽  
Qiang Zhang ◽  
Saiyue Liu ◽  
Bingcheng Luo ◽  
Eongyu Yi ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Squeeze Casting ◽  
Thermal Mismatch ◽  
Mismatch Strain

Fully dense Y2Mo3O12/Al composites were prepared by squeeze casting.

Alucone Interlayers to Minimize Stress Caused by Thermal Expansion Mismatch between Al2O3 Films and Teflon Substrates

2013 ◽  
Vol 5 (3) ◽  
pp. 1165-1173 ◽  
Author(s):  
Shih-Hui Jen ◽  
Steven M. George ◽  
Robert S. McLean ◽  
Peter F. Carcia
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Mismatch ◽  
Al2o3 Films

Shape forming by thermal expansion mismatch and shape memory locking in polymer/elastomer laminates

2017 ◽  
Vol 26 (10) ◽  
pp. 105027 ◽  
Author(s):  
Chao Yuan ◽  
Zhen Ding ◽  
T J Wang ◽  
Martin L Dunn ◽  
H Jerry Qi
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Thermal Expansion Mismatch

Rapid shear alignment of sub-10 nm cylinder-forming block copolymer films based on thermal expansion mismatch

Nano Futures ◽  
2018 ◽  
Vol 1 (3) ◽  
pp. 035006
Author(s):  
Samuel M Nicaise ◽  
Karim R Gadelrab ◽  
Amir Tavakkoli K G ◽  
Caroline A Ross ◽  
Alfredo Alexander-Katz ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Block Copolymer ◽  
Thermal Expansion Mismatch ◽  
Shear Alignment ◽  
Copolymer Films

Pressureless Co-Sintering of Al2O/ZrO2 Multilayers and Bilayers

1996 ◽  
Vol 434 ◽  
Author(s):  
Peter Z. Cai ◽  
David J. Green ◽  
Gary L. Messing
Keyword(s):  
Thermal Expansion ◽  
Cyclic Loading ◽  
Microscopic Observation ◽  
Surface Defects ◽  
Tape Casting ◽  
Thermal Expansion Mismatch ◽  
Heating Rates ◽  
The Difference ◽  
Extent Of Damage ◽  
Transverse Damage

AbstractVarious types of damage were observed in pressureless-sintered Al2O3/ZrO2 symmetric laminates (multilayers) and asymmetric laminates (bilayers) fabricated by tape casting and lamination. These defects included channel defects in ZrO2-containing layers, Al2O3 surface defects parallel to the layers, decohesion between the layers, and transverse damage within the Al2O3 layer in the bilayers. Detailed microscopic observation attributed the defects to a combined effect of mismatch in both sintering rate and thermal expansion coefficient between the layers. Crack-like defects were formed in the early stages of densification, and these defects acted as pre-existing flaws for thermal expansion mismatch cracks. Curling of the bilayers during sintering was monitored and the measured rate of curvature change, along with the layer viscosities obtained by cyclic loading dilatometry, was used to estimate the sintering mismatch stresses. The extent of damage could be reduced or even eliminated by decreasing the difference in layer sintering rate. This was accomplished by reducing the heating rates or by adding Al2O3 in the ZrO2 layers.

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