A Study of the Photoluminescence and Reflectivity Spectra of MOCVD Grown MnSe

1994 ◽  
Vol 340 ◽  
Author(s):  
M. Di Blasio ◽  
L. Aigouy ◽  
M. Averous ◽  
J. Calas ◽  
P. Tomasini ◽  
...  
Keyword(s):  
Energy Gap ◽  
Stokes Shift ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zinc Blende ◽  
Reflectivity Spectra ◽  
Different Temperatures ◽  
First Time ◽  
Zinc Blende Structure

Photoluminescence (PL) experiments at 2K are performed on MOCVD grown MnSe. The precursors used in the growth stage are methylpentacarbonylmanganese and diethylselenide. Pyrolysis of the percursors is realized inside a gradient reactor under a constant H2 flux, between 280-55°TC. The compound is epitaxially grown on various substrates (Si, InP, GaSb, GaAs, ZnTe/GaAs, etc.). On some of these samples the compound presents a zinc blende structure, while in the other samples rock salt formation has been identified. The first substrate is used because of its interest in Si technology, while the others are used because MnSe can be grown in the zinc blende phase for very thin layers. For the first time x-ray diffraction data has allowed us to determine the lattice constant of zincblende MnSe (aMnse (oct)=5.818Å), confirming the close approximation (a ∼ 5.9Å) used from the Zn1-xMnxSe alloy. These compounds have visible Mn++ transitions at 2.12-5eV; other features are also visible at 2.3-4, 2.7, and 3.0eV. The energy gap transition of tetrahedral thin film layers of MnSe is seen for the first time in PL spectra. A temperature dependant PL study is performed on MnSe in the 2-200K range. Reflectivity experiments are used to attempt to identify the internal manganese transitions. A qualitative PL analysis of the samples grown at different temperatures and on different substrates is provided. A Stokes shift is encountered when the results are compared.

Photoreflectance Characterization of InGaAs Lattice Matched to InP

1993 ◽  
Vol 324 ◽  
Author(s):  
V. Bellani ◽  
M. Amiotti ◽  
M. Geddo ◽  
G. Guizzetti ◽  
G. Landgren
Keyword(s):  
Energy Gap ◽  
Lattice Mismatch ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Interfacial Strain ◽  
Valence Bands ◽  
Lattice Matched

AbstractWe measured photoreflectance (PR) spectra at different temperatures between 80 and 300 K, and optical absorption (OA) at 3 K on MOVPE grown Inl-xGaxAs nearly lattice-matched to InP. x-ray diffraction measurements gave a lattice mismatch δa/ao = -0.9.10−3 between ternary alloy and InP, corresponding to × = 0.485. We obtained the energy gap dependence on T from PR spectra. The blue shift of the gap was accounted for in terms of compositional difference with respect to the perfectly lattice matched alloy (× = 0.472), and elastic strain; moreover PR and OA showed evidence of the valence bands splitting at k = 0 due to interfacial strain, in fine agreement with theory.

Epitaxial growth of skutterudite (CoSb3) thin films on (001) InSb by pulsed laser deposition

2001 ◽  
Vol 16 (9) ◽  
pp. 2467-2470 ◽  
Author(s):  
J. C. Caylor ◽  
M. S. Sander ◽  
A. M. Stacy ◽  
J. S. Harper ◽  
R. Gronsky ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Zinc Blende Structure

Heteroepitaxial growth of the cubic skutterudite phase CoSb3 on (001) InSb substrates was achieved by pulsed laser deposition using a substrate temperature of 270 °C and a bulk CoSb3 target with 0.75 at.% excess Sb. An InSb (a0 = 4 0.6478 nm) substrate was chosen for its lattice registry with the antimonide skutterudites (e.g., CoSb3 with a = 0 4 0.9034 nm) on the basis of a presumed 45° rotated relationship with the InSb zinc blende structure. X-ray diffraction and transmission electron microscopy confirmed both the structure of the films and their epitaxial relationship: (001)CoSb3 ∥ (001)InSb; [100]CoSb3 ∥ [110]InSb.

Preparation and Performance Characterization of “Turnjujube-Like” CdSe Nanofibers

2014 ◽  
Vol 971-973 ◽  
pp. 123-126
Author(s):  
Yong Ping Luo ◽  
Zong Hu Xiao ◽  
Shun Jian Xu ◽  
Wei Zhong ◽  
Huan Wen Wu ◽  
...  
Keyword(s):  
Structure Characterization ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
Cubic Crystal ◽  
X Ray ◽  
Zinc Blende ◽  
And Performance ◽  
First Time

It was reported for the first time that “Turnjujube-like” CdSe nanofibers have been assembled onto TiO2surface by electrochemical method of cyclic voltammetry, using CdSO4•8H2O and SeO2as raw material, can be used as a sensitizer of quantum dot-sensitized solar cell. CdSe morphology, structure characterization and optical properties are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and ultraviolt-visible spectroscopy (UV–Vis), respectively. The experimental results show that the prepared “Turnjujube–like” CdSe nanofibers are zinc blende CdSe with cubic crystal system, and it have excellent light absorption within the wavelength range of 300–800 nm. It has a potential for the construction of QD-sensitized solar energy cell.

Selective Growth of Gold onto Copper Indium Sulfide Selenide Nanoparticles

2013 ◽  
Vol 68 (5) ◽  
pp. 398-404 ◽  
Author(s):  
Elena Witt ◽  
Jürgen Parisi ◽  
Joanna Kolny-Olesiak
Keyword(s):  
Hybrid Nanostructures ◽  
Indium Sulfide ◽  
X Ray Diffraction ◽  
Gold Nanocrystals ◽  
X Ray ◽  
Copper Indium Disulfide ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Copper Indium ◽  
Zinc Blende Structure

Hybrid nanostructures are interesting materials for numerous applications in chemistry, physics, and biology, due to their novel properties and multiple functionalities. Here, we present a synthesis of metal-semiconductor hybrid nanostructures composed of nontoxic I-III-VI semiconductor nanoparticles and gold. Copper indium sulfide selenide (CuInSSe) nanocrystals with zinc blende structure and trigonal pyramidal shape, capped with dodecanethiol, serve as an original semiconductor part of a new hybrid nanostructure. Metallic gold nanocrystals selectively grow onto vertexes of these CuInSSe pyramids. The hybrid nanostructures were studied by transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and UV-Vis-absorption spectroscopy, which allowed us conclusions about their growth mechanism. Hybrid nanocrystals are generated by replacement of a sacrificial domain in the CuInSSe part. At the same time, small selenium nanocrystals form that stay attached to the remaining CuInSSe/Au particles. Additionally, we compare the synthesis and properties of CuInSSe-based hybrid nanostructures with those of copper indium disulfide (CuInS2). CuInS2/Au nanostructures grow by a different mechanism (surface growth) and do not show any selectivity.

F-Centers and Oxygen-Interstitials in MgO

1992 ◽  
Vol 279 ◽  
Author(s):  
C. Scholz ◽  
P. Ehrhart
Keyword(s):  
Optical Absorption Spectroscopy ◽  
Assisted Migration ◽  
X Ray Diffraction ◽  
Migration Process ◽  
X Ray ◽  
Different Temperatures ◽  
Induced Defects ◽  
First Time ◽  
Irradiation Induced Defects ◽  
Cascade Damage

ABSTRACTMgO single crystals have been irradiated at different temperatures (4 K, 300 K) with electrons of energies varying between 0.3 and 3 MeV. The irradiation induced defects and their reactions during thermal annealing have been investigated by optical absorption spectroscopy and by X-ray diffraction. The relaxation volume (Viel ≈ 1 at.vol. = a3/8) and the migration energy of the interstitial atoms (≈ 1.6 eV) are determined and an ionization induced and thermally assisted migration process is observed for the first time. The relevance of these results for the understanding of the cascade damage observed after neutron- or ion-damage is discussed.

A new method for analysing peak broadening caused by compositional fluctuation in X-ray diffraction measurements

2001 ◽  
Vol 34 (6) ◽  
pp. 681-690
Author(s):  
Kiichi Nakashima ◽  
Yoshihiro Kawaguchi
Keyword(s):  
New Method ◽  
Theoretical Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compositional Fluctuation ◽  
Zinc Blende ◽  
Difference Variable ◽  
Peak Broadening ◽  
New Criterion ◽  
Zinc Blende Structure

A new method for analysing X-ray peak broadening caused by compositional fluctuation is proposed. The method is applicable to epitaxial layers with diamond or zinc-blende structure on (001) substrates. In the new method, a rescaling procedure with a difference variable ΔAis applied to measured X-ray profiles and the dependence of the profiles on various reflection indiceshklis analysed. The theoretical formula reveals that X-ray peak profiles become independent ofhklafter the rescaling. A new criterion is proposed; an experimental examination based on the criterion makes it possible simply to judge whether or not X-ray peak broadening is caused by compositional fluctuation. The method is verified experimentally and demonstrated by applying it to an InGaAs multilayer sample having artificial compositional fluctuation.

In Situ Deposition of CuBiS2 on Mesoporous TiO2 Film for Light Absorber in Solar Cells

2020 ◽  
Vol 20 (12) ◽  
pp. 7748-7752
Author(s):  
Peng-Cheng Wang ◽  
Feng-Zhu Li ◽  
Yu Zhang ◽  
Hao-Chen Fan ◽  
Xue-Qin Zhou ◽  
...  
Keyword(s):  
Energy Gap ◽  
Spectral Absorption ◽  
X Ray Diffraction ◽  
Solid Reaction ◽  
X Ray ◽  
In Situ Deposition ◽  
Light Absorber ◽  
Pure Phase ◽  
First Time

In this report, emplectite (CuBiS2) semiconductor has been deposited on mesoporous TiO2 using gas–solid reaction method. For the first time, CuCl2 and BiCl3 are solution-coated on mesoporous TiO2 films, and thereafter reacted with H2S gas in an H2S atmosphere. The CuBiS2 film is further confirmed using X-ray diffraction; thus, demonstrating the pure phase of CuBiS2. CuBiS2 film shows high spectral absorption with an energy gap (Eg) of 2.18 eV. Furthermore, devices have a structure consisting of FTO/compact-TiO2/mesoporous-TiO2/CuBiS2/P3HT/Ag have been fabricated and hence exhibit high photoresponse performance.

Structural and magnetic property studies on BaREBiO4 (where RE = Sm and Nd) system

2014 ◽  
Vol 28 (23) ◽  
pp. 1450156 ◽  
Author(s):  
A. Manigandan ◽  
V. Anbarasu ◽  
B. Sathyaseelan ◽  
K. Sivakumar
Keyword(s):  
Effective Magnetic Moment ◽  
Room Temperature ◽  
Energy Gap ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Gap Measurement ◽  
Ceramic Compounds ◽  
First Time

The new ceramic compounds type BaREBiO 4 (where RE = Sm and Nd ) have been reported for the first time. The sample was prepared by solid-state reaction technique. The orthorhombic crystallization with a = 6.429(4) Å, b = 6.536(5) Å, c = 8.648(4) Å for BaSmBiO 4 and a = 6.485(3) Å, b = 6.561(4) Å, c = 8.686(4) Å for BaNdBiO 4 was studied from powder X-ray diffraction studies. The semiconducting nature of the compounds was observed with the energy gap measurement from diffused reflectance spectroscopy (DRS) studies. The paramagnetic nature of the compounds at room temperature and low temperature conditions was identified by magnetization measurements as a function of magnetic fields and temperature. The effective magnetic moment of the samples was found to be 2.126 μB and 4.272 μB.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

scholarly journals First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer
Keyword(s):  
Natural Zeolite ◽  
Scanning Electron Micrographs ◽  
Total Sulfur ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
The World ◽  
Porosity And Permeability ◽  
First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

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