scholarly journals Improved optical activation of ion-implanted Zn acceptors in GaN by annealing under N2 overpressure

1997 ◽  
Vol 2 ◽  
Author(s):  
A. Pelzmann ◽  
S. Strite ◽  
A. Dommann ◽  
C. Kirchner ◽  
Markus Kamp ◽  
...  
Keyword(s):  
Optical Quality ◽  
X Ray Diffraction ◽  
High Optical Quality ◽  
X Ray ◽  
Mocvd Reactor ◽  
Defect Annealing ◽  
Optical Activation ◽  
Gan Crystal ◽  
Ion Implanted

We investigated the properties of ion-implanted GaN:Zn annealed under various conditions using photoluminescence (PL) and high resolution x-ray diffraction (HRXRD). Epitaxial GaN/sapphire of high optical quality was ion-implanted with a 1013 cm−2 dose of Zn+ ions at 200 keV. The sample was capped with 200 Å of SiNx and then diced into numerous pieces which were annealed under varied conditions in an attempt to optically activate the Zn. Annealing was performed in a tube furnace under flowing N2, an atmospheric pressure MOCVD reactor under flowing NH3 or N2, and under an N2 overpressure of 190 atm. The observed improvement in the optical quality of GaN:Zn annealed under N2 overpressure yields further insights into the trade-off between defect annealing and N loss from the GaN crystal.

Investigations on growth and property of mid-infrared lithium selenoindate single crystals

2016 ◽  
Vol 30 (21) ◽  
pp. 1650290
Author(s):  
Li Dai ◽  
Chao Tan ◽  
Zhehua Yan ◽  
Yuheng Xu
Keyword(s):  
Vickers Hardness ◽  
Optical Quality ◽  
Front Face ◽  
Horizontal Temperature Gradient ◽  
X Ray Diffraction ◽  
Damage Resistance ◽  
High Optical Quality ◽  
Vickers Hardness Number ◽  
X Ray ◽  
Back Face

Lithium selenoindate (LiInSe2) crystals with high optical quality are successfully grown by small-angle inclined horizontal temperature gradient condensation. In order to evaluate the various characteristics, the powder X-ray diffraction (XRD) spectrum, optical damage resistance ability and Vickers hardness in lithium selenoindate crystals were studied. The growth crystals have orthorhombic nature, a = 6.184 Å, b = 7.092 Å and c = 8.207 Å. The damage thresholds of LiInSe2 crystal with the front face and back face were 224 mW/cm2 and 165 mW/cm2. Also the Vickers hardness number of LiInSe2 crystal was found to be 342.4 kg/mm2.

Properties of Zn Implanted GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
S. Strite ◽  
P. W. Epperlein ◽  
A. Dommann ◽  
A. Rockett ◽  
R. F. Broom
Keyword(s):  
Room Temperature ◽  
Optical Quality ◽  
N Loss ◽  
X Ray ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Optical Activation ◽  
Low Efficiency ◽  
Secondary Ion

ABSTRACTWe report the optical and structural properties of ion implanted GaN:Zn. Post-implant annealing up to 1100 °C was performed under flowing N2 in both a tube furnace and a rapid thermal annealing (RTA) system, with and without SiNx encapsulation layers. The implantation damage is quantified by transmission electron microscopy (TEM). Secondary ion mass spectroscopy (SIMS) detects significant rearrangement of implanted Zn only at the highest temperatures and doses investigated. Strain reduction, observed in GaN:Zn annealed at or above 975 °C by high-resolution x-ray diffractometry (HRXRD), indicates successful damage removal. The optical activation of annealed GaN:Zn is measured by photoluminescence (PL). The room temperature (RT) Zn acceptor transition at ∼430 nm is consistently observed in annealed GaN:Zn, but at low efficiency. We conclude that residual implantation damage and/or N loss during annealing limits the optical quality of implanted GaN:Zn.

X-ray Diffraction Study of InGaN/GaN Superlattice Implanted with Eu3+ Ions

2009 ◽  
Vol 1202 ◽  
Author(s):  
Mohammad Ahmad Ebdah ◽  
Martin E. Kordesch ◽  
Andre Anders ◽  
Wojciech M. Jadwisienczak
Keyword(s):  
Chemical Vapor ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
Gradual Improvement ◽  
X Ray ◽  
Different Temperatures ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Ion Implanted

AbstractIn this work, europium implanted InGaN/GaN SL with a fixed well/barrier thickness ratio grown by metal-organic chemical-vapor deposition (MOCVD) on GaN/(0001) sapphire substrate were investigated. The as-grown and Eu ion implanted InGaN/GaN SLs were annealed at different temperatures ranging from 600°C to 950°C in nitrogen ambient. The quality of the SL interfaces in undoped and implanted structures has been investigated by X-ray diffraction (XRD) at room temperature. The characteristic satellite peaks of SLs were measured for the (0002) reflection up to the second order in the symmetric Bragg geometry. The XRD simulation spectrum of the as-grown SL agrees well with the experimental results. The simulation results show x=0.06 atomic percent the InGaN well sub-layers, with thicknesses of 2.4 and 3.3 nm for single InGaN well and GaN barrier, respectively. It was observed that annealing of the undoped SL does not significantly affect the interfacial quality of the superstructure, whereas, the Eu ion implanted InGaN/GaN SL undergo partial induced degradation. Annealing the implanted SLs shows a gradual improvement of the multilayer periodicity and a reduction of the induced degradation with increasing the annealing temperature as indicated by the XRD spectra.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Study of the quality of GaAs thin film on Si substrate by X-ray diffraction method

1990 ◽  
Vol 7 (7) ◽  
pp. 308-311
Author(s):  
Li Chaorong ◽  
Mai Zhenhong ◽  
Cui Shufan ◽  
Zhou Junming ◽  
Yutian Wang
Keyword(s):  
Thin Film ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray

scholarly journals High temperature structural study of decagonal Al-Cu-Rh quasicrystal.

2014 ◽  
Vol 70 (a1) ◽  
pp. C94-C94
Author(s):  
Pawel Kuczera ◽  
Walter Steurer
Keyword(s):  
Structural Changes ◽  
Configurational Entropy ◽  
Lattice Vibrations ◽  
X Ray Diffraction ◽  
Stabilization Mechanism ◽  
X Ray ◽  
Comparative Structure ◽  
The Stability

The structure of d(ecagonal)-Al-Cu-Rh has been studied as a function of temperature by in-situ single-crystal X-ray diffraction in order to contribute to the discussion on energy or entropy stabilization of quasicrystals (QC) [1]. The experiments were performed at 293 K, 1223 K, 1153 K, 1083 K, and 1013 K. A common subset of 1460 unique reflections was used for the comparative structure refinements at each temperature. The results obtained for the HT structure refinements of d-Al-Cu-Rh QC seem to contradict a pure phasonic-entropy-based stabilization mechanism [2] for this QC. The trends observed for the ln func(I(T1 )/I(T2 )) vs.|k⊥ |^2 plots indicate that the best on-average quasiperiodic order exists between 1083 K and 1153 K, however, what that actually means is unclear. It could indicate towards a small phasonic contribution to entropy, but such contribution is not seen in the structure refinements. A rough estimation of the hypothetic phason instability temperature shows that it would be kinetically inaccessible and thus the phase transition to a 12 Å low T structure (at ~800 K) is most likely not phason-driven. Except for the obvious increase in the amplitude of the thermal motion, no other significant structural changes, in particular no sources of additional phason-related configurational entropy, were found. All structures are refined to very similar R-values, which proves that the quality of the refinement at each temperature is the same. This suggests, that concerning the stability factors, some QCs could be similar to other HT complex intermetallic phases. The experimental results clearly show that at least the ~4 Å structure of d-Al-Cu-Rh is a HT phase therefore entropy plays an important role in its stabilisation mechanism lowering the free energy. However, the main source of this entropy is probably not related to phason flips, but rather to lattice vibrations, occupational disorder unrelated to phason flips like split positions along the periodic axis.

Crystalline and Electrical Properties of Ferroelectric Silver Niobate-tantalate thin Films

2000 ◽  
Vol 655 ◽  
Author(s):  
Jung-Hyuk Koh ◽  
S.I. Khartsev ◽  
Alex Grishin ◽  
Vladimir Petrovsky
Keyword(s):  
Temperature Stability ◽  
Frequency Dispersion ◽  
Processing Temperature ◽  
High Temperature Stability ◽  
X Ray Diffraction ◽  
Ferroelectric State ◽  
X Ray ◽  
Ferroelectric Hysteresis ◽  
First Time

AbstractFor the first time AgTa0.38Nb0.62O3 (ATN) films have been grown on the La0.7Sr0.3CoO3 (LSCO)/LaAlO3 single crystal as well as onto Pt80Ir20 (PtIr) polycrystalline substrate. Comprehensive X-ray diffraction analyses reveal epitaxial quality of ATN and LSCO films on the LaAlO3(001) substrate, while ATN/PtIr films have been found to be (001) preferentially oriented. Dielectric spectroscopy performed for ATN films and bulk ceramics in a wide temperature range 77 to 420 K shows the structural monoclinic M1-to-monoclinic M2 phase transition occurs in films at the temperature 60 °C lower than in ceramics. The tracing of the ferroelectric hysteresis P-E loops indicates the ferroelectric state in ATN films at temperatures below 125 K and yields remnant polarization of 0.4 μC/cm2 @ 77 K. Weak frequency dispersion, high temperature stability of dielectric properties as well as low processing temperature of 550 °C make ATN films to be attractive for various applications.

Characterization of Natural and Synthesized FeTiO3 Crystals With RBS/PIXE/XRD

1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ion Beam ◽  
Pressure Control ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beam Analysis ◽  
Ppm Level

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.

Sign in / Sign up

Export Citation Format

Share Document