Influence Of Compressive Strain Research Articles

Study on the Influence of Plane Strain on Optical Properties of InP Materials through First-Principles Calculations

This research scrutinizes the impact of plane strain on the optical characteristics of Indium Phosphide (InP) employing first-principles methodology, grounded on the Density Functional Theory (DFT). The findings suggest that the peaks of the spectral response curves of the dielectric function, refractive index, extinction coefficient, optical absorption coefficient, and reflection coefficient of InP, when subjected to plane tension strain, shift towards lower energy of electromagnetic wave frequency in the horizontal coordinate. Concurrently, static quantities such as the dielectric coefficient, refractive coefficient, and reflection coefficient of InP demonstrate an upward trend with an increase in the plane tension strain. Intriguingly, the influence of compressive strain on the photoelectric response of InP manifests contrary behavior to that of the tensile strain.

Influence of compressive strain on the hydrogen storage capabilities of graphene: a density functional theory study

Pristine graphene is not suitable for hydrogen storage at ambient conditions since it binds the hydrogen molecules only by van der Waals interactions. However, the adsorption energy of the hydrogen molecules can be improved by doping or decorating metal atoms on the graphene monolayer. The doping and decoration processes are challenging due to the oxygen interference in hydrogen adsorption and the clustering issue of metal atoms. To improve the hydrogen adsorption energy in pristine graphene, we have explored the hydrogen storage capabilities of graphene monolayer in the presence of compressive strain. We found that at 6 % of biaxial compressive strain, a 4*4*1 supercell of graphene can adsorb 10 H$_2$ molecules above the graphene surface. The average binding energy of H$_2$ for this configuration is found to be -0.42 eV/H$_2$, which is very suitable for reversible hydrogen adsorption. We propose that a 4*4*1 supercell of graphene can adsorb a total number of 20 H$_2$ molecules leading to a high hydrogen uptake of 9.4 %. The interaction between orbitals of carbon and hydrogen atoms and the charge transfer process have been studied by plotting the partial density of states and surface charge density plots. The electronic density around the C-C bonds of graphene increases in the presence of compressive strain, due to which hydrogen molecules are strongly adsorbed.

Overcoming the excessive compressive strain in AlGaN epitaxy by introducing high Si-doping in AlN templates

The influence of compressive strain in high-quality AlN templates on the subsequent growth of AlGaN-based device layers was investigated. The AlN templates showed compressive strain of ∼−0.29% and threading dislocation densities (TDDs) below 6.5 × 108 cm−2. By introducing high Si-doping in MOVPE-grown AlN, the compressive strain was relaxed while preserving the low TDD. By this method, the low TDD was transferred from the AlN template to the micron-thick n-Al0.63Ga0.37N. A 275 nm LED was demonstrated with a ∼2.5 times power enhancement than the same LED on conventional MOVPE-grown AlN template under low current injection. The maximum external quantum efficiency (EQE) was enhanced from 1.6% to 2.2% with an improved n-AlGaN.

Strain induced electronic and magnetic properties of 2D magnet CrI3: a DFT approach

In the post-graphene era, out of several monolayer 2D materials, Chromium triiodide () has triggered an exotic platform for studying the intrinsic ferromagnetism and large anisotropy at the nanoscale regime. Apart from that, its strong spin–orbit coupling of I also plays a key role in tailoring the electronic properties. In this work, the composition of compressive and tensile strain (uniaxial as well as biaxial) upto 12% have been applied to study the variation of the electronic and magnetic properties of employing density functional theory in (LDA+U) exchange correlation scheme. The stability limits of the structures under the influence of strains have been carried out via the deformation potential (DP) and stress–strain relation. For compressive strains in specific directions, the down-spin band gap is seen to be decreasing steadily. The magnetic moment computed from the density of states (DOS) is enhanced significantly under the influence of compressive strain. However, it has been observed that after the application of strain in some specific crystal directions, the magnetic moment of monolayer remains almost unchanged. Thus, with the help of strain, the tunning band gap along with underlying characteristic ferromagnetism of this material can unfold a new avenue for potential usage in spintronic devices.

Influence of compressive strain on the microstructural evolution of an AlCoCrFeNi high entropy alloy

Suction-cast AlCoCrFeNi equiatomic high entropy alloy rods were prepared, and then the development of microstructure was investigated by the progress of annealing and compression at 1100°C. Both film-type and particle-shape fcc grains were generated at the expense of disordered A2 bcc at the initial stage of annealing. However, prior coarse bcc grains still remained without any sign of lattice rotation, recrystallization, or grain refinement by the progress of annealing. By high-temperature compression at 1100°C, phase transformation, twin boundary generation, and dynamic recrystallization play a significant role in the refinement of both the newly generated fcc and the remained B2 bcc grains. Since brittle and disordered A2 bcc region was replaced by fine, equiaxed, soft and tough fcc phase, multi-phase refining of suction-cast AlCoCrFeNi HEA can be proposed as a promising structural materials having considerable ductility without much expense of strength by means of feasible thermomechanical processing.

Tuning Optical Properties of MoS2 Bulk and Monolayer Under Compressive and Tensile Strain: A First Principles Study

Knowledge of the optical properties under compressive and tensile strain is highly important in photoelectron devices and the semiconductor industry. In this work, optical properties of bulk and monolayer MoS2 under compressive and tensile strains are investigated by means of density functional theory. The dielectric tensor is derived within the random phase approximation. Calculations indicate that unstrained two-dimensional and bulk MoS2 lead to semiconductors with the gaps of 1.64 eV and 0.84 eV, respectively, whereas the change in the value of the gap by applying tensile or compressive strain depends on the nature of strains. Dielectric function, absorption coefficient, reflectivity, energy loss and the refraction index of the strained and unstrained systems are studied for both parallel (E||x) and perpendicular (E||z) applied electric field polarizations, which are very sensitive to the type and amount of strains. For instance, the reflectivity of a MoS2 monolayer exposed to visible light in the E||z polarization direction, can be tuned from 4% to 10% by introducing strain. Finally, the Abbe number is calculated to characterize the dispersion of the materials under compressive and tensile strain. Bulk MoS2 for E||x shows the highest value of the Abbe number, which shrinks twenty times under the influence of compressive strain.

Flexible Complementary Oxide–Semiconductor-Based Circuits Employing n-Channel ZnO and p-Channel SnO Thin-Film Transistors

In this letter, we report flexible fully oxide-based complementary metal–oxide–semiconductor (CMOS) inverters and ring oscillators by the monolithic integration of flexible n-channel zinc oxide (ZnO) and p-channel tin monoxide (SnO) thin-film transistors (TFTs). Inverted-staggered bottom-gated TFTs were fabricated by a low-temperature RF-sputtering technique. The static voltage gain of a flexible oxide-TFT-based CMOS inverter with a geometric aspect ratio of 5 is $\sim 12$ at a supplied voltage ( $\text{V}_{\mathrm {DD}}$ ) of 12 V. An oscillation frequency of $\sim 18.4$ kHz is obtained from a five-stage flexible oxide-TFT-based CMOS voltage control ring oscillator at $\text{V}_{\mathrm {DD}}$ of 12 V. Degradations of TFTs, inverters, and ring oscillators have been observed when a mechanical tensile strain is applied, whereas the influence of compressive strain is negligible.

Strain-induced matrix-dependent deformation of GaAs nanoparticles

The influence of compressive strain on the deformation of GaAs nanoparticles embedded in different host matrices is investigated. The simulation results indicate that it can be easier to deform GaAs nanoparticles grown in an Al2O3 film than those in an SiO2 film. The deformation induced by the applied compressive strain has significant influence on the shape, size and microstructure of GaAs nanoparticles. Most significantly, these simulated results have a good agreement with HRTEM experimental results.

Influence of compressive strain on oxygen distribution in La0.7Ba0.3MnO3 thin films

The effects of annealing ambient on the structural and transport properties of epitaxial La0.7Ba0.3MnO3 films suffering large compressive strain on LaAlO3 substrates (LBMO/LAO) have been investigated. Independent of oxygen or argon ambient, a high temperature (900 °C) post-annealing process leads to a c-axis contraction, which can be attributed to the oxygen transfer from the in-plane to the out-of-plane direction. Meanwhile, the transport properties are similar with each other for both the Ar-annealed and O2-annealed films. The comparison of the ambient annealing effects between the highly strained LBMO/LAO films and negligibly strained LBMO films on SrTiO3 substrates indicates that a large in-plane compressive strain favors decreasing oxygen deficiency in the films, especially in the ab-plane.

Influence of compressive strain on the arsenic incorporation in MOVPE-grown InAsP/InP single quantum wells

In this paper we have studied the effect of MOVPE growth conditions on the arsenic incorporation in strained InAsP quantum wells (QWs) grown on InP substrates. Lower growth temperatures result in an enhanced arsenic incorporation, as well as an improvement in the quality of the heterostructure. It is seen that an increase in the arsine flux does not readily increase the arsenic composition in the film which is dependent on temperature, strain and growth conditions.

Mössbauer study of static and dynamic critical behavior in Fe

In this paper we present the results of detailed experimental studies on the critical behavior of Fe near its critical temperature ${T}_{c}$ (here also Curie temperature ${T}_{C}$) using the M\"ossbauer effect. Using a highly controlled two-stage M\"ossbauer furnace, we made a careful measurement of the critical exponent $\ensuremath{\beta}$ and the critical exponent $z$. The value of ${\ensuremath{\beta}}_{\mathrm{eff}}$ was obtained in both source and absorber experiments and was found to be 0.379(4) for the reduced-temperature range ${10}^{\ensuremath{-}3}<~t<~2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$ and 0.371(8) for ${10}^{\ensuremath{-}4}<~t<~2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$, respectively. We have used correction-to-scaling form in the critical region and have obtained the universal $\ensuremath{\beta}$ as $\ensuremath{\beta}=0.367(5)$ and the correction amplitude $A=\ensuremath{-}0.458(22)$. The results on $\ensuremath{\beta}$ agree well with theory, bulk measurements on Fe, and most data on other ferromagnets in the universality class $(n,d)=(3,3)$. The value $z$ was measured as $z=1.93(19)$, which is inconsistent with the theory of short-range exchange interactions and neutron scattering results in Fe, but in agreement with previous hyperfine studies on Ni and Fe, and a recent hypothesis on the dynamic behavior in the asymptotic critical region. We have also investigated the possible magnetization dependence of the isomer shift in Fe and obtained negative results, both within 2 K of the Curie point, and in a wide region above and below the Curie point. These findings, like the $\ensuremath{\beta}$ measurements, are based on both source and absorber experiments. They disagree with Preston's observations near ${T}_{c}$. By studying the M\"ossbauer line intensities we observed a magnetostrictive reorientation of ferromagnetic domains as a function of temperature. This behavior is similar to that observed in some Fe alloys under the influence of compressive strain as well as temperature variation.