Enhancement of photoluminescence and hole mobility in 1- to 5-layer InSe due to the top valence-band inversion: strain effect

Nanoscale ◽  
2018 ◽  
Vol 10 (24) ◽  
pp. 11441-11451 ◽  
Author(s):  
Meng Wu ◽  
Jun-jie Shi ◽  
Min Zhang ◽  
Yi-min Ding ◽  
Hui Wang ◽  
...  
Keyword(s):  
Valence Band ◽  
Compressive Strain ◽  
Hole Mobility ◽  
Strain Effect ◽  
Direct Bandgap ◽  
Band Inversion

The great enhancement of photoluminescence and hole mobility in few-layer InSe due to an indirect-to-direct bandgap transition under 6% compressive strain.

scholarly journals Strain and ligand effects in Pt-Ni alloys studied by valence-to-core X-ray emission spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiatang Chen ◽  
Y. Zou Finfrock ◽  
Zhiqiang Wang ◽  
Tsun-Kong Sham
Keyword(s):  
Valence Band ◽  
Emission Spectroscopy ◽  
Compressive Strain ◽  
High Energy ◽  
Reduction Reaction ◽  
High Energy Resolution ◽  
Strain Effect ◽  
Ligand Effect ◽  
X Ray ◽  
Ni Alloys

AbstractExperimental detection of the Pt 5d densities of states in the valence band is conducted on a series of Pt-Ni alloys by high energy resolution valence-to-core X-ray emission spectroscopy (VTC-XES) at the Pt L3-edge. VTC-XES measurements reveal that the Pt d-band centroid shifts away from the Fermi level upon dilution, accompanied by concentration-dependent Pt d-band width. The competition between the strain effect and ligand effect is observed experimentally for the first time. It is found that the d-band widths in Pt3Ni and PtNi are broader than that of Pt metal due to compressive strain which overcompensates the effect of dilution, while it is narrower in PtNi3 where the ligand effect dominates. VTC-XES is demonstrated to be a powerful tool to study the Pt d-band contribution to the valence band of Pt-based bimetallic. The implication for the enhanced activity of Pt-Ni catalysts in oxygen reduction reaction is discussed.

Compressive strain dependence of hole mobility in strained Ge channels

2005 ◽  
Vol 87 (19) ◽  
pp. 192102 ◽  
Author(s):  
K. Sawano ◽  
Y. Abe ◽  
H. Satoh ◽  
Y. Shiraki ◽  
K. Nakagawa
Keyword(s):  
Compressive Strain ◽  
Hole Mobility ◽  
Strain Dependence

scholarly journals E-kRelation of Valence Band in Arbitrary Orientation/Typical Plane Uniaxially Strained

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Zhang Chao ◽  
Xu Da-Qing ◽  
Liu Shu-Lin ◽  
Liu Ning-Zhuang
Keyword(s):  
Valence Band ◽  
Theoretical Basis ◽  
Carrier Mobility ◽  
Energy Levels ◽  
Hole Mobility ◽  
Strained Si ◽  
Effective Masses ◽  
Splitting Energy ◽  
Analytic Models ◽  
Strained Materials

Uniaxial strain technology is an effective way to improve the performance of the small size CMOS devices, by which carrier mobility can be enhanced. TheE-krelation of the valence band in uniaxially strained Si is the theoretical basis for understanding and enhancing hole mobility. The solving procedure of the relation and its analytic expression were still lacking, and the compressive results of the valence band parameters in uniaxially strained Si were not found in the references. So, theE-krelation has been derived by taking strained Hamiltonian perturbation into account. And then the valence band parameters were obtained, including the energy levels at Γ point, the splitting energy, and hole effective masses. Our analytic models and quantized results will provide significant theoretical references for the understanding of the strained materials physics and its design.

Superlattice Interface and Lattice Strain Study by Ion Channeling

1983 ◽  
Vol 25 ◽  
Author(s):  
C. K. Pan ◽  
D. C. Zheng ◽  
W. K. Chu ◽  
C.-A. Chang
Keyword(s):  
Lattice Strain ◽  
Ion Beam ◽  
Compressive Strain ◽  
Angular Position ◽  
Angle Measurement ◽  
Strain Effect ◽  
Individual Layer ◽  
Ion Channeling ◽  
Kink Angle ◽  
Good Agreement

EXTENDED ABSTRACTWe have studied the interface and the lattice strain of superlattices by ion channeling technique. The objective in this work is to verify the existence of alternating tensile and compressive strain in the superlattice and to develop a method for measuring the lattice strain directly. Alternating layers of GaSb/Al Sb were grown epitaxially by MBE with 10 periods. The thickness of each individual layer is 30 nm. Channeling measurements and analysis were made using a 1.76 MeV 4He ion beam. The measurements reveal higher dechanneling along the [110] axis than along the [100] axis. This is consistent with the dechanneling results published earlier. The high dechanneling along the [110] axis has been considered due to the lattice strain that occurs in the layers caused by the slight mismatch between the lattice constants of the two materials. The strain effect make [110] axis slightly bent from layer to layer (“zigzag”), but it does not occur in [100] axis. The axial angular scan analyses were made around the [110] direction at the different depths using a movable energy window setting. We have found that the angular position of the best alignment shifts from layer to layer. The oscillation of those angular positions with depth is of a direct evidence of the existence of alternating tension and compression strain layers in the superlattice. The “kink” angle at the interface is given by the difference of the angular position between the first and second layer. This is found to be 0.17° ± 0.03 %. This is in a good agreement with the result calculated from elasticity. Preliminary result of this experiment is recently published.3We are also investigating the interface and lattice strain by planar angular scan across the (110) plane at a position three degrees from [110] axis.The similar oscillatory results have been found for {110} planar channeling and the “kink” angle measurement is in a good agreement with the results from axial angular scan.We believe that the method of ion beam channeling and angular scan is very effective in strain measurements in multi-layered heteroexpitaxy system.3. W. K. Chu, C. K. Pan and C.-A. Chang, Phys. Rev. Rapid Communication B28, 4033 (1983).

Characterization of InN-In0.25Ga0.75N Quantum Well Laser with In0.4Al0.6N Layers for 1300 nm Band

MRS Advances ◽  
2016 ◽  
Vol 1 (28) ◽  
pp. 2051-2057 ◽  
Author(s):  
Md. Mobarak Hossain Polash ◽  
Kamruzzaman Khan
Keyword(s):  
Optical Properties ◽  
Numerical Model ◽  
Quantum Well ◽  
Electronic Band Structure ◽  
Compressive Strain ◽  
Strain Effect ◽  
Transition Elements ◽  
Electronic Band ◽  
Layer Width ◽  
Quantum Well Laser

ABSTRACTA wurtzite-strained nitride Quantum Well Laser has been characterized for short distance communication wavelength. InN and In0.25Ga0.75N have been chosen as well material and barrier material respectively with In0.4Al0.6N SCH layers at the end of barrier layers to improve the carrier and photon confinement within the active region. This structure shows less compressive strain (7.33%) with respect to previously proposed structure which makes the structure more suitable for fabrication. To obtain the electronic band structure, self-consistent method with k.p formalism has been performed where valence band mixing effect, strain effect and spontaneous and piezoelectric polarization effect has been included. From the electronic characteristics, the optical properties have been performed with numerical model. From the optical properties, the structure has been found as TE polarized with C1-HH1, C1-LH1, C2-HH1 and C2-LH1 dominating transition elements. From the performance of the numerical model, 4731.98 cm−1 optical gain for TE polarization at 1315.5 nm emission wavelength and 8.017×1027 cm−3s−1eV−1 spontaneous emission rate at 1301.7nm wavelength have been found for 12Å well width, 17Å barrier width and 52Å SCH layer width at 5×1019 cm−3 carrier density. The obtained properties have been shown a good agreement with previously published works.

Strain effect on the catalytic activities of B- and B/N-doped black phosphorene for electrochemical conversion of CO to valuable chemicals

2020 ◽  
Vol 8 (24) ◽  
pp. 11986-11995
Author(s):  
Zhe Chen ◽  
Xin Liu ◽  
Jingxiang Zhao ◽  
Yan Jiao ◽  
Lichang Yin
Keyword(s):  
Compressive Strain ◽  
Strain Effect ◽  
Metal Free ◽  
Catalytic Activities ◽  
Electrochemical Conversion ◽  
Black Phosphorene

Designed metal-free electrocatalysts combined with compressive strain can efficiently convert CO to valuable chemicals and fuels.

scholarly journals Transformation of the Topological Phase and the Edge Modes of Double-Bilayer Bismuthene with Inter-Bilayer Spacing

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 266 ◽  
Author(s):  
Huanzhi Hu ◽  
Zhibin Shi ◽  
Peng Wang ◽  
Weiping Zhou ◽  
Tai-Chang Chiang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Valence Band ◽  
Conduction Band ◽  
Topological Insulator ◽  
First Principles ◽  
Topological Phase ◽  
First Principles Calculations ◽  
Topological Phase Transition ◽  
Band Inversion ◽  
Band Insulator

The transformations of the topological phase and the edge modes of a double-bilayer bismuthene were investigated with first-principles calculations and Green’s function as the inter-bilayer spacing increased from 0 Å to 10 Å. At a critical spacing of 2 Å, a topological phase transition from a topological insulator to a band insulator resulting from a band inversion between the highest valence band and the second lowest conduction band, was observed, and this was understood based on the particular orbital characters of the band inversion involved states. The edge modes of double-bilayer bismuthene survived the phase transition. When d was 2 Å < d < 4 Å, the interaction between the edge modes of two separated bismuthene bilayers induced an anti-crossing gap and resulted in a trivial band connection. At and beyond 4 Å, the two bilayers behavior decoupled entirely. The results demonstrate the transformability of the topological phase and the edge modes with the inter-bilayer spacing in double-bilayer bismuthene, which may be useful for spintronic applications.

Anisotropic Strain Effect on Electron Transport in C60 Organic Field Effect transistors

2013 ◽  
Vol 1501 ◽  
Author(s):  
Akash Nigam ◽  
Günther Schwabegger ◽  
Mujeeb Ullah ◽  
Rizwan Ahmed ◽  
Ivan I. Fishchuk ◽  
...  
Keyword(s):  
Electron Transport ◽  
Charge Transport ◽  
Field Effect ◽  
High Performance ◽  
Tensile Strain ◽  
Field Effect Transistors ◽  
Compressive Strain ◽  
Strain Effect ◽  
Wearable Electronics ◽  
Organic Field Effect Transistors

ABSTRACTMechanical flexibility is one of the key advantages of organic semiconducting films in applications such as wearable-electronics or flexible displays. The present study is aimed at gaining deeper insight into the effect of strain on charge transport properties of the organic semiconductor films. We have fabricated high performance C60 top gate organic field effect transistors (OFET) on flexible substrates and characterized the devices by curling the substrates in concave and convex manner, to apply varying values of compressive and tensile strain, respectively. Electron mobility is found to increase with compressive strain and decrease with tensile strain. The observed strain effect is found to be strongly anisotropic with respect to the direction of flow of current. This observation on mobility is quantified using an Extended Gaussian Disorder Model (EGDM) for the hopping charge transport. We suggest that the observed strain dependence of the electron transport is dominated by a change in the effective charge hopping distance over the grain boundaries in polycrystalline C60 films.

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