Compositional dependence of the bowing parameter for the direct and indirect band gaps in Ge1−ySny alloys

2014 ◽  
Vol 105 (14) ◽  
pp. 142102 ◽  
Author(s):  
J. D. Gallagher ◽  
C. L. Senaratne ◽  
J. Kouvetakis ◽  
J. Menéndez
Keyword(s):  
Band Gaps ◽  
Compositional Dependence ◽  
Bowing Parameter

scholarly journals Physical, Optical, and Spectroscopic Studies on MgO-BaO-B2O3 Glasses

ISRN Ceramics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Samdani ◽  
Md. Shareefuddin ◽  
G. Ramadevudu ◽  
S. Laxmi Srinivasa Rao ◽  
M. Narasimha Chary
Keyword(s):  
Optical Absorption ◽  
Urbach Energy ◽  
Glass Composition ◽  
Glass Network ◽  
Spectroscopic Studies ◽  
Band Gaps ◽  
Compositional Dependence ◽  
Paramagnetic Resonance ◽  
Optical Band Gaps ◽  
Electron Paramagnetic

The mixed alkaline effect in double alkaline borate glasses MgO-BaO-B2O3 containing small proportions of copper oxide (CuO) has been studied. The glass samples are characterized by optical absorption, electron paramagnetic resonance (EPR), and Fourier transform infrared spectroscopy (FTIR). A red shift in optical absorption peaks with increasing MgO (decreasing BaO) concentration has been observed. The values of “g” tensor and hyperfine “A” tensor have shown inflections with glass composition. The number of spins (N) and paramagnetic susceptibility (χ) also exhibited mixed alkaline effect. The broadening of glass network with increase in MgO concentration is found from the FTIR spectra. Interestingly both density and molar volume have shown decreasing trend with glass composition. The optical band gaps exhibited a nonlinear compositional dependence. As expected, the glass samples possessed higher values of optical basicity (Λ), molar electronic polarizability (αm), and Urbach energy (ΔE).

Compositional dependence of the bowing parameter for highly strained InGaAs/GaAs quantum wells

2009 ◽  
Vol 80 (16) ◽  
Author(s):  
T. K. Sharma ◽  
R. Jangir ◽  
S. Porwal ◽  
R. Kumar ◽  
Tapas Ganguli ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Compositional Dependence ◽  
Bowing Parameter ◽  
Highly Strained

ENERGY BAND-GAPS OF MgxZn1-xSe: VIOLATION OF VEGARD'S LAW

2004 ◽  
Vol 18 (01) ◽  
pp. 137-142 ◽  
Author(s):  
Z. CHARIFI ◽  
H. BAAZIZ ◽  
N. BOUARISSA
Keyword(s):  
Energy Band ◽  
Composition Dependence ◽  
Composition Range ◽  
Band Gaps ◽  
Ternary Alloys ◽  
Lattice Constants ◽  
Bowing Parameter ◽  
Zinc Blende ◽  
System Transition ◽  
Vegard’S Law

Based on a pseudopotential scheme, the composition dependence of energy band-gaps of zinc-blende Mg x Zn 1-x Se ternary alloys in the composition range of 0≤x≤1 are determined. The effect of deviation of lattice constants of the alloys of interest from Vegard's law on the optical bowing parameter and system transition between the direct and indirect structures is discussed.

Phonon Band Gaps

1997 ◽  
Vol 7 (3) ◽  
pp. 509-519 ◽  
Author(s):  
R. M. Hornreich ◽  
M. Kugler ◽  
S. Shtrikman ◽  
C. Sommers
Keyword(s):  
Band Gaps ◽  
Phonon Band

Dibenzochrysene Enables Tightly Controlled Docking and Stabilizes Photoexcited States in Dual-Pore Covalent Organic Frameworks

2019 ◽  
Author(s):  
Torben Sick ◽  
Niklas Keller ◽  
Nicolai Bach ◽  
Andreas Koszalkowski ◽  
Julian Rotter ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Photophysical Properties ◽  
Visible Spectrum ◽  
Large Family ◽  
Building Blocks ◽  
Band Gaps ◽  
Docking Site ◽  
Covalent Organic Frameworks ◽  
Connected Node ◽  
Optoelectronic Applications

Covalent organic frameworks (COFs), consisting of covalently connected organic building units, combine attractive features such as crystallinity, open porosity and widely tunable physical properties. For optoelectronic applications, the incorporation of heteroatoms into a 2D COF has the potential to yield desired photophysical properties such as lower band gaps, but can also cause lateral offsets of adjacent layers. Here, we introduce dibenzo[g,p]chrysene (DBC) as a novel building block for the synthesis of highly crystalline and porous 2D dual-pore COFs showing interesting properties for optoelectronic applications. The newly synthesized terephthalaldehyde (TA), biphenyl (Biph), and thienothiophene (TT) DBC-COFs combine conjugation in the a,b-plane with a tight packing of adjacent layers guided through the molecular DBC node serving a specific docking site for successive layers. The resulting DBC-COFs exhibit a hexagonal dual-pore kagome geometry, which is comparable to COFs containing another molecular docking site, namely 4,4′,4″,4‴-(ethylene-1,1,2,2-tetrayl)-tetraaniline (ETTA). In this context, the respective interlayer distances decrease from about 4.60 Å in ETTA-COFs to about 3.6 Å in DBC-COFs, leading to well-defined hexagonally faceted single crystals sized about 50-100 nm. The TT DBC-COFs feature broad light absorption covering large parts of the visible spectrum, while Biph DBC-COF shows extraordinary excited state lifetimes exceeding 10 ns. In combination with the large number of recently developed linear conjugated building blocks, the new DBC tetra-connected node is expected to enable the synthesis of a large family of strongly p-stacked, highly ordered 2D COFs with promising optoelectronic properties.

Flexural Wave Band Gaps in Phononic Crystal Thick Plates with Defects

2019 ◽  
Author(s):  
Edson Jansen Pedrosa de Miranda Junior ◽  
Jose Maria Campos dos Santos
Keyword(s):  
Phononic Crystal ◽  
Band Gaps ◽  
Flexural Wave ◽  
Wave Band ◽  
Thick Plates

Simulating Photonic Band Gaps in Crystals

2007 ◽  
Author(s):  
Daniel H. Kodan ◽  
Peter W. Chung
Keyword(s):  
Band Gaps ◽  
Photonic Band Gaps ◽  
Photonic Band
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