scholarly journals Effect of temperature on isotopic mass dependence of excitonic band gaps in semiconductors: ZnO

2007 ◽  
Vol 75 (20) ◽  
Author(s):  
H. Alawadhi ◽  
S. Tsoi ◽  
X. Lu ◽  
A. K. Ramdas ◽  
M. Grimsditch ◽  
...  
Keyword(s):  
Band Gaps ◽  
Effect Of Temperature ◽  
Mass Dependence ◽  
Excitonic Band

Isotopic-mass dependence of the A, B, and C excitonic band gaps inZnOat low temperatures

2006 ◽  
Vol 74 (16) ◽  
Author(s):  
S. Tsoi ◽  
X. Lu ◽  
A. K. Ramdas ◽  
H. Alawadhi ◽  
M. Grimsditch ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Band Gaps ◽  
Mass Dependence ◽  
Excitonic Band

A method for evaluating the ground state excitonic band gaps of strained InxGa1−xN/GaN quantum wells

2009 ◽  
Vol 106 (10) ◽  
pp. 104509 ◽  
Author(s):  
T. K. Sharma ◽  
E. Towe
Keyword(s):  
Quantum Wells ◽  
Ground State ◽  
Band Gaps ◽  
Excitonic Band

scholarly journals Effect of Temperature on Photonic Band Gaps in Semiconductor-Based One-Dimensional Photonic Crystal

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
J. V. Malik ◽  
K. D. Jindal ◽  
Vinay Kumar ◽  
Vipin Kumar ◽  
Arun Kumar ◽  
...  
Keyword(s):  
Refractive Index ◽  
Photonic Band Gap ◽  
Semiconductor Material ◽  
Band Gaps ◽  
Effect Of Temperature ◽  
Angle Of Incidence ◽  
Propagation Characteristics ◽  
Photonic Band Gaps ◽  
One Dimensional ◽  
Photonic Band

The effect of the temperature and angle of incidence on the photonic band gap (PBG) for semiconductor-based photonic crystals has been investigated. The refractive index of semiconductor layers is taken as a function of temperature and wavelength. Three structures have been analyzed by choosing a semiconductor material for one of the two materials in a bilayer structure. The semiconductor material is taken to be ZnS, Si, and Ge with air in first, second, and third structures respectively. The shifting of band gaps with temperature is more pronounced in the third structure than in the first two structures because the change in the refractive index of Ge layers with temperature is more than the change of refractive index of both ZnS and Si layers with temperature. The propagation characteristics of the proposed structures are analyzed by transfer matrix method.

The General Synthesis of Nanostructured V/VI Semiconductors

2004 ◽  
Vol 829 ◽  
Author(s):  
Paul Christian ◽  
Paul O'Brien
Keyword(s):  
Band Gap ◽  
Narrow Band ◽  
Band Gaps ◽  
Effect Of Temperature ◽  
Capping Agent ◽  
Thermo Electric ◽  
Alkyl Amines ◽  
General Synthesis ◽  
Long Chain ◽  
General Method

ABSTRACTSemiconductors in the V/VI series have band gaps ranging from 2.2 eV for Sb2S3 to 0.21 eV for Bi2Te3 spanning the range seen from conventional mid to narrow band gap materials to semi-metals. These materials, especially those with narrower band gaps, demonstrate thermo-electric properties and are used in Peltier devices. There are examples in the literature of the synthesis of several of these materials in a nanostructured form, however the reactions often rely on highly toxic reagents, especially in the case of tellurium containing materials. Further more there are no reports of general routes applicable to all three chalcogenides.In this paper we describe a general method for the synthesis of chalcogenide V/VI nanomaterials by the reaction of acetate salts with the corresponding chalcogenide under reflux conditions in long chain alkyl amines, typically octylamine or dodecylamine. The effect of temperature and capping agent on the morphology of the final product are discussed and in particular the synthesis of Bi2S3 nanorods, Bi2Se3 and Bi2Te3 nanowafers and Sb2Se3 nanowires are described.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum

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
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