Optical emission characteristics of (Cu, Ag)In(Se, Te)2 pentenary alloys

1985 ◽  
Vol 63 (6) ◽  
pp. 781-785 ◽  
Author(s):  
T. M. Vanderwel ◽  
L. P. McNeil ◽  
P. E. Jessop ◽  
B. K. Garside
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Optical Emission ◽  
Face Centered Cubic ◽  
Group Vi ◽  
Electronic Band ◽  
Phase Transition Temperatures ◽  
High Emission ◽  
Thermal Analyser ◽  
Face Centered

Chalcopyrite alloys with the composition (Cu(1−x)Agx)In(Se(1−z)Tez)2 have been synthesized and characterized. X-ray powder-diffraction measurements show well-defined single-phase material at each composition, verifying complete miscibility. Lattice parameters and differential-thermal-analyser-determined phase-transition temperatures vary smoothly throughout the composition range. Luminescence measurements have been obtained for a large range of excess carrier levels, and characteristics of the electronic band structure have been inferred by comparison of the observed spectra with spectra calculated using a recently developed model.At all compositions, the short, interband, luminescence decay time and the relatively high emission intensity identify the bandgap as direct. The results of the luminescence analysis also indicate that the band structure is dominated by a shallow acceptor ((Ea–Ev) = 10 to 40 meV), except in the AgInSe2 corner where the acceptor concentration drops low enough to allow a donor at (Ec–Ed) = 55 meV to take precedence. Alloying of the group VI anion causes a significant decrease in the bandgap, which drops to almost 100 meV below the minimum monochalcogen value. There is also a large increase in the concentration of the acceptor, which indicates that this acceptor is due to imperfections in the anion face-centered cubic (fcc) sublattice.

scholarly journals Structural building principles of complex face-centered cubic intermetallics

2011 ◽  
Vol 67 (4) ◽  
pp. 269-292 ◽  
Author(s):  
Julia Dshemuchadse ◽  
Daniel Y. Jung ◽  
Walter Steurer
Keyword(s):  
Chemical Composition ◽  
Crystal Structures ◽  
Electronic Band Structure ◽  
Layer Structure ◽  
Repeat Unit ◽  
Basic Structure ◽  
Group Symmetry ◽  
Face Centered Cubic ◽  
Electronic Band ◽  
Face Centered

Fundamental structural building principles are discussed for all 56 known intermetallic phases with approximately 400 or more atoms per unit cell and space-group symmetry F\bar{4}3m, Fd\bar{3}m, Fd\bar{3}, Fm\bar{3}m or Fm\bar{3}c. Despite fundamental differences in chemical composition, bonding and electronic band structure, their complex crystal structures show striking similarities indicating common building principles. We demonstrate that the structure-determining elements are flat and puckered atomic {110} layers stacked with periodicities 2p. The atoms on this set of layers, which intersect each other, form pentagon face-sharing endohedral fullerene-like clusters arranged in a face-centered cubic packing (f.c.c.). Due to their topological layer structure, all these crystal structures can be described as (p × p × p) = p 3-fold superstructures of a common basic structure of the double-diamond type. The parameter p, with p = 3, 4, 7 or 11, is determined by the number of layers per repeat unit and the type of cluster packing, which in turn are controlled by chemical composition.

The electronic band structure of silicon

Physica ◽  
1954 ◽  
Vol 3 (7-12) ◽  
pp. 967-970
Author(s):  
D JENKINS
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band

THE ELECTRONIC BAND STRUCTURE OF V3Ga AND V3Si

1972 ◽  
Vol 33 (C3) ◽  
pp. C3-223-C3-233 ◽  
Author(s):  
I. B. GOLDBERG ◽  
M. WEGER
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band

Ab initio calculation on the Optical Properties of AA- Stacked two dimensional Graphene, Silicene, Germanene, and Stanene

2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Complex Refractive Index ◽  
Single Layer ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Wide Range ◽  
Optical Region

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.

scholarly journals Electronic Band Structure and Transport Properties of the Cluster Compound Ag3Tl2Mo15Se19

2019 ◽  
Vol 58 (9) ◽  
pp. 5533-5542 ◽  
Author(s):  
Patrick Gougeon ◽  
Philippe Gall ◽  
Rabih Al Rahal Al Orabi ◽  
Benoit Boucher ◽  
Bruno Fontaine ◽  
...  
Keyword(s):  
Band Structure ◽  
Transport Properties ◽  
Electronic Band Structure ◽  
Cluster Compound ◽  
Electronic Band
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