scholarly journals Effect of Substrate Biasing on the Epitaxial Growth and Structural Properties of RF Magnetron Sputtered Germanium Buffer Layer on Silicon

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1060
Author(s):  
Gui-Sheng Zeng ◽  
Chi-Lung Liu ◽  
Sheng-Hui Chen
Keyword(s):  
Single Crystal ◽  
Lattice Constant ◽  
High Efficiency ◽  
Buffer Layers ◽  
Crystalline Quality ◽  
Raman Shift ◽  
Full Width ◽  
Half Maximum ◽  
Si Substrates ◽  
Diffraction Patterns

High-quality single-crystal-like Ge (004) thin films have been epitaxially grown using radio-frequency magnetron sputtering on Si (001) substrates successfully. The crystalline quality of the Ge films can be obviously improved by applying a positive bias on the substrate holder. X-ray diffraction measurements show that the single-crystal-like Ge film has a narrow full width at half maximum of 0.26°. The perpendicular lattice constant (aGe⊥) and in-plane lattice constant (aGe∥) are 0.5671 and 0.564 nm. The Raman shift full width at half maximum shows that the defects in the film are obviously reduced. Transmission electron microscopy diffraction patterns also show that the Ge (004) film has good crystalline quality. The results can be applied as Ge buffer layers on Si substrates for the fabrication of high-efficiency III–V solar cells and photodetectors.

La cristallinité de l'illite revisitée: un bilan des connaissances acquises ces trente dernières années

Clay Minerals ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 143-157 ◽  
Author(s):  
B. Kübler ◽  
D. Goy-Eggenberger
Keyword(s):  
Clay Minerals ◽  
Full Width ◽  
Half Maximum ◽  
X Ray Diffraction ◽  
Illite Crystallinity ◽  
X Ray ◽  
Diffraction Patterns ◽  
Gaseous Hydrocarbons ◽  
Definition Of ◽  
Technological Improvements

AbstractThe main reason for the initial determinations of illite crystallinity (IC) was to support the exploration for liquid and gaseous hydrocarbons. The application in 1960 of the Weaver Sharpness Ratio to core materials of a borehole from eastern France indicated that it was not a reliable tool for identifying well-crystallized illite. This ratio was later replaced by the Full Width at Half-Maximum (FWHM), the value of which decreases regularly and consistently towards greenschist facies. The use of FWHM allowed a precise definition of the anchimetamorphic zone between the upper diagenesis and the epimetamorphism. Afterwards, analysis of weak-tointermediate diagenetic sequences showed that illite crystallinity decreases together with the amount of swelling interlayers in mixed-layer clay minerals. Technological improvements, such as computing and modelling of X-ray diffraction patterns, increased the analytical precision relative to measurements of the plain FWHM. Consequently, illite crystallinity went back to its initial use, namely detection of the transitions between diagenesis, anchi- and epi-metamorphism in smectitefree lithologies, where it can be used as a stratigraphic and mineralogic marker of alteration stages.

High-efficiency vertical-structure GaN-based light-emitting diodes on Si substrates

2018 ◽  
Vol 6 (7) ◽  
pp. 1642-1650 ◽  
Author(s):  
Wenliang Wang ◽  
Yunhao Lin ◽  
Yuan Li ◽  
Xiaochan Li ◽  
Liegen Huang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Light Emitting ◽  
Si Substrates ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

High-quality GaN-based light-emitting diode (LED) wafers have been grown on Si substrates by metal–organic chemical vapor deposition by designing epitaxial structures with AlN/Al0.24Ga0.76N buffer layers and a three-dimensional (3D) GaN layer.

scholarly journals Phase Polymorphism, Molecular Motions and Structural Changes in [Cr(NH3)6](ClO4)3

2007 ◽  
Vol 62 (3-4) ◽  
pp. 179-186 ◽  
Author(s):  
Edward Mikuli ◽  
Natalia Górska ◽  
Stanisław Wróbel ◽  
Jacek Ściesińskic ◽  
Ewa Ściesińska
Keyword(s):  
Phase Transition ◽  
Structural Changes ◽  
Full Width ◽  
Half Maximum ◽  
Molecular Motions ◽  
Scanning Calorimetry ◽  
Phase Polymorphism ◽  
Temperature Dependences ◽  
Diffraction Patterns ◽  
Fir Spectra

A phase transition in [Cr(NH3)6](ClO4)3 at Thc = 293.5 K (on heating) and Tcc = 293.0 K (on cooling) was determined by differential scanning calorimetry. The temperature dependences of the full width at half maximum of the bands connected with ρr(NH3)F1u and δd(ClO)E modes suggest that the discovered phase transition is not connected with drastic changes in the speed of reorientational motions of the NH3 ligands nor the ClO4 − anions. Temperature dependence of the FT-FIR spectra and the diffraction patterns show that the discovered phase transition is caused by a change in the crystal structure.

Growth of Improved GaAs/Si: Suppression of Volmer-Weber Nucleation for Reduced Threading Dislocation Density

1998 ◽  
Vol 535 ◽  
Author(s):  
P. J. Taylor ◽  
W.A. Jesser ◽  
G. Simonis ◽  
W. Chang ◽  
M. Lara-Taysing ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Single Crystal ◽  
Threading Dislocation ◽  
Full Width ◽  
Half Maximum ◽  
Growth Technique ◽  
X Ray ◽  
Threading Dislocation Density ◽  
Island Coalescence ◽  
Initial Deposition

AbstractThe growth of reduced dislocation density GaAs/Si is performed by a novel two-step technique where the first epitaxy step takes place at 75° C and the second is performed at 580° C. The initial deposition is single crystal, continuous, and planar such that there is no contribution to the dislocation density from Volmer-Weber island coalescence and no trapping of dislocations in pinholes. Using this new growth technique, a reduced dislocation density the order of 106/cm2 was obtained. The improved crystallinity is indicated by the more narrow x-ray full-width-at-half-maximum (FWHM) value of 110 arcseconds. GaAs p-i-n diodes were grown on the reduced dislocation density GaAs/Si and it was found that the resistivity of the intrinsic region for the heteroepitaxial diodes was similar to homoepitaxial ones for small mesa sizes.

Crystallographic Analysis of (110)CeO2/(100)Si Using RBS/Channeling Technique

1993 ◽  
Vol 312 ◽  
Author(s):  
Masataka Satoh ◽  
Yasuhiro Yamamoto ◽  
Shigeyuki Nakajima ◽  
Yoshinobu Sakurai ◽  
Tomoyasu Inoue ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystallographic Analysis ◽  
Crystalline Quality ◽  
Depth Information ◽  
Planar Channeling ◽  
Si Substrate ◽  
Si Substrates

AbstractEpitaxially grown CeO2 layers on (100)Si substrates are studied using the RBS/channeling technique. The crystallographic correlation between the overgrown layers and off-oriented Si substrates is precisely analyzed by means of constructing stereographic projections obtained from the planar channeling dips. From the stereographic projections for the CeO2 layer on the 4° off-oriented Si substrate, it is clearly seen not only that the epitaxial (110)CeO2 layer is single crystal with the direction defined as [001]CeO2 ║ [011]Si, but also that the crystalline quality of (110)CeO2 on (100)Si can be improved by use of the off-oriented substrate. The inclined epitaxial direction is also detected as the depth information.

Electron diffraction analysis of a metastable state in ion-irradiated MgAl2O4 spinel

1995 ◽  
Vol 53 ◽  
pp. 160-161
Author(s):  
Ram Devanathan ◽  
Ning Yu ◽  
Kurt E. Sickafus ◽  
Michael Nastasi
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Lattice Constant ◽  
Metastable State ◽  
Fast Neutrons ◽  
Bravais Lattice ◽  
Energetic Ions ◽  
Radiation Resistant ◽  
Diffraction Patterns ◽  
First Time

Magnesium aluminate spinel is considered to be a remarkably radiation resistant material. Single crystal spinel exhibits very little damage when irradiated with fast neutrons or energetic ions. Recently, amorphization of single-crystal MgAl204 was observed, for the first time, following irradiation with 400 keV Xe2+ at about 100 K to a peak dose of 25 dpa. Electron diffraction patterns from spinel subjected to different doses show the extinction of first-order fundamental reflections prior to the occurence of amorphization. This suggests that, enroute to becoming amorphous, ion-irradiated spinel transforms to a metastable crystalline state with a lattice constant that is half that of spinel. In an effort to understand this phase transformation, we have analyzed the structure of the metastable state using electron diffraction.Spinel belongs to the spacegroup Fd3m (fee Bravais lattice). The unit cell has a lattice constant of about 0.8 nm and is made of two sets of four octants.

Kyropoulos Growth and Characterization of Monoclinic α-Bi2B8O15 Single Crystal with Noncentrosymmetric Structure

CrystEngComm ◽  
2021 ◽  
Author(s):  
Mengdi Fan ◽  
guangda wu ◽  
Xinle Wang ◽  
Fapeng Yu ◽  
Chun Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Full Width ◽  
Half Maximum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Borate Crystal ◽  
Kyropoulos Method

Monoclinic bismuth-based borate crystal α-Bi2B8O15 was grown by the Kyropoulos method. High resolution X-ray diffraction analysis showed that the full width at half-maximum of the Y plate was about 0.04°...

Heteroepitaxial Growth of In203 on Ysz (100) Single Crystal Surface

1999 ◽  
Vol 558 ◽  
Author(s):  
M. Orita ◽  
H. Ohta ◽  
H. Tanji ◽  
H. Hosono ◽  
H. Kawazoe
Keyword(s):  
Single Crystal ◽  
Crystal Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Full Width ◽  
Half Maximum ◽  
Single Crystal Surface ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTIn203 films were deposited on YSZ (001) single crystal surface at 800°C at an oxygen pressure of 14 Pa by pulsed laser deposition (PLD) method. A heteroepitaxial relationship between the film and the substrate was seen in TEM photographs and X-ray diffraction measurements. The w locking curve full width of half maximum (FWHM) of the In203 (004) x-ray diffraction was 0.06°. Film conductivities were ∼10 S/cm or less, while carriers on the order of lO18/cm3 were generated.

Quasi-single Crystal Semiconductors on Glass Substrates Through Biaxially Oriented Buffer Layers

2010 ◽  
Vol 1268 ◽  
Author(s):  
Toh-Ming Lu ◽  
Huafang Li ◽  
Churamani Gaire ◽  
Nicholas LiCausi ◽  
Tzu Liang Chan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Pole Figure ◽  
High Efficiency ◽  
High Energy ◽  
Buffer Layers ◽  
Oblique Angle Deposition ◽  
Semiconductor Films ◽  
Single Crystalline ◽  
Glass Substrates ◽  
Volume Production

AbstractHigh efficiency photovoltaic devices are normally fabricated on single crystalline substrates. These single crystalline substrates are expensive and volume production for widespread usage has not been realistic. To date, large volume production of solar cells is on less expensive non-crystalline substrates such as glass. Typically the films grown on glass are polycrystalline with less than ideal efficiency. It was proposed that a dramatic gain in the efficiency may be achieved if one uses a biaxially oriented buffer layer on glass to grow biaxial semiconductor films to fabricate solar devices compared to that of films grown directly on glass. Biaxial films are not exactly single crystal but have strongly preferred crystallographic orientations in both the out-of-plane and in-plane directions. Typically the misorientation between grains can be small (within a few degrees) and may possess low carrier recombination rate. In this paper we shall discuss growth techniques that would allow one to produce biaxial buffer layers on glass. A specific strategy using an atomic shadowing mechanism in an oblique angle deposition configuration that allows one to grow biaxial buffer layers such as CaF2on glass substrate will be discussed in detail. Results of heteroepitaxy of semiconductor materials such as CdTe and Ge on these biaxial buffer/glass substrates characterized by x-ray pole figure, reflection high energy electron diffraction (RHEED) pole figure and transmission electron microscopy (TEM) will be presented.

Diffraction of 100 to 200 keV X-rays from an Si1−x Ge x gradient crystal: comparison with results from dynamical theory

1999 ◽  
Vol 55 (5) ◽  
pp. 855-863 ◽  
Author(s):  
Steffen Keitel ◽  
Cécile Malgrange ◽  
Thomas Niemöller ◽  
Jochen R. Schneider
Keyword(s):  
Critical Value ◽  
Dynamical Theory ◽  
X Rays ◽  
Full Width ◽  
Half Maximum ◽  
Strain Gradients ◽  
Normal Absorption ◽  
Diffraction Patterns ◽  
Laue Geometry ◽  
Good Agreement

In a large Czochralski-grown Si1−x Ge x (0.02 \leq x \leq 0.07) gradient crystal, diffraction patterns have been measured in symmetrical Laue geometry using synchrotron radiation in the energy range 100–200 keV. The experimental data are in very good agreement with the results from geometrical optics theory for distorted crystals, if the creation of new wavefields for strain gradients larger than a critical value is taken into account. In this sense, the crystal behaves like an ideal gradient crystal. If the normal absorption is disregarded, for reflection 111 and 100 keV energy, the full width at half-maximum values and the peak reflectivities of the diffraction patterns range from 14.6′′ and 97%, respectively, to 70.9′′ and 74%, respectively, for a variation in the Ge concentration from 3.5 to 5.3 at.%.

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