Propagation of threading dislocations and effects of Burgers vectors in HVPE-grown GaN bulk crystals on Na-flux-grown GaN substrates

2021 ◽  
Vol 129 (22) ◽  
pp. 225701
Author(s):  
T. Hamachi ◽  
T. Tohei ◽  
Y. Hayashi ◽  
M. Imanishi ◽  
S. Usami ◽  
...  
Keyword(s):  
Threading Dislocations ◽  
Bulk Crystals

Photoluminescence Study of Plastically Deformed GaN

2004 ◽  
Vol 831 ◽  
Author(s):  
I. Yonenaga ◽  
H. Makino ◽  
S. Itoh ◽  
T. Goto ◽  
T. Yao
Keyword(s):  
Plastic Deformation ◽  
Near Band Edge ◽  
Threading Dislocations ◽  
Yellow Luminescence ◽  
Bulk Crystals ◽  
Prismatic Plane ◽  
Free Standing ◽  
Yellow Band ◽  
Band Edge Luminescence ◽  
Red Luminescence

ABSTRACTWe report the photoluminescence characteristics of fresh dislocations introduced by the plastic deformation in GaN bulk crystals. GaN crystals prepared from free standing wafers grown by the HVPE technique were compressed plastically at 900 to 1000°C. In the deformed crystals (a/3) (1120) dislocations on the (1110) prismatic plane, corresponding to the so-called threading dislocations, were observed in TEM. In the PL studies at 11K the intensity of the near band-edge luminescence decreased drastically in the deformed GaN by about 1/12 than that of the as-grown GaN, which seems to imply the introduction of a high density of non-radiative reco!m bination centers into GaN! during the plastic deformation. By the plastic deformation the yellow band luminescence decreased remarkably meanwhile the red band and other new luminescence developed relatively. It is found that dislocations do not originate to the yellow luminescence but the red luminescence.

Dislocation Behavior in Bulk Crystals Grown by TSSG Method

2018 ◽  
Vol 924 ◽  
pp. 39-42 ◽  
Author(s):  
Kazuaki Seki ◽  
Kazuhiko Kusunoki ◽  
Yutaka Kishida ◽  
Hiroshi Kaido ◽  
Koji Moriguchi ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Conversion Efficiency ◽  
Solution Method ◽  
Bulk Crystal ◽  
Threading Dislocations ◽  
Bulk Crystals ◽  
Bulk Crystal Growth ◽  
X Ray ◽  
Bulk Growth ◽  
Dislocation Behavior

The dislocation behavior during bulk crystal growth on the 4H-SiC (000-1) C-face using the solution method was investigated. A 2 inch wafer with a 4° off angle was fabricated from a bulk crystal grown by the TSSG method, and the dislocations in the crystal were evaluated using synchrotron X-ray topography and TEM observation. From the topograph images, it was found that the TSD density remarkably decreased as the growth progressed. Furthermore, the TEM observation suggested that TSD decreases as the threading dislocations convert to in-plane defects toward the center of the crystal. Conventionally, it was considered that conversion of threading dislocations hardly occurs in solution growth on the C-face. However, it is thought that this phenomenon was not observable because the conversion efficiency is remarkably low. We speculate that dislocations may be transformed by suddenly making macrosteps during bulk growth.

Lattice imaging and pore structure of β ferric oxyhydroxide

1978 ◽  
Vol 36 (1) ◽  
pp. 264-265
Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bulk Material ◽  
Model Structure ◽  
Bulk Crystals ◽  
Lattice Imaging ◽  
Thin Sections ◽  
Ferric Oxyhydroxide ◽  
Resolution Electron ◽  
Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

Anisotropy of interfacial defects in the initial stage of MOVPE GaAs growth On Si

1990 ◽  
Vol 48 (4) ◽  
pp. 592-593
Author(s):  
C. Vannuffel ◽  
C. Schiller ◽  
J. P. Chevalier
Keyword(s):  
Early Stage ◽  
Threading Dislocations ◽  
Mbe Growth ◽  
Detailed Mechanism ◽  
Si Substrates ◽  
Initial Stage ◽  
Interfacial Defects ◽  
Interfacial Dislocations ◽  
Step Growth ◽  
Essential Problem

Recently, interest has focused on the epitaxy of GaAs on Si as a promising material for electronic applications, potentially for integration of optoelectronic devices on silicon wafers. The essential problem concerns the 4% misfit between the two materials, and this must be accommodated by a network of interfacial dislocations with the lowest number of threading dislocations. It is thus important to understand the detailed mechanism of the formation of this network, in order to eventually reduce the dislocation density at the top of the layers.MOVPE growth is carried out on slightly misoriented, (3.5°) from (001) towards , Si substrates. Here we report on the effect of this misorientation on the interfacial defects, at a very early stage of growth. Only the first stage, of the well-known two step growth process, is thus considered. Previously, we showed that full substrate coverage occured for GaAs thicknesses of 5 nm in contrast to MBE growth, where substantially greater thicknesses are required.

Relation of Heat Transfer with the Growth Rate of InSb based Bulk Crystals Grown by VDS and its Effect on the Crystal Quality

2020 ◽  
Vol 12 (2) ◽  
pp. 02012-1-02012-5
Author(s):  
Dilip Maske ◽  
◽  
Manisha Deshpande ◽  
Dattatray Gadkari ◽  
◽  
...  
Keyword(s):  
Heat Transfer ◽  
Growth Rate ◽  
Crystal Quality ◽  
Bulk Crystals

Local current leakage at threading dislocations in GaN bulk single crystals grown by a modified Na-flux method

2019 ◽  
Vol 58 (5) ◽  
pp. 050918 ◽  
Author(s):  
Takeaki Hamachi ◽  
Tetsuya Tohei ◽  
Masayuki Imanishi ◽  
Yusuke Mori ◽  
Akira Sakai
Keyword(s):  
Single Crystals ◽  
Threading Dislocations ◽  
Flux Method ◽  
Current Leakage ◽  
Local Current ◽  
Bulk Single Crystals

Misfit and threading dislocations in HgCdTe epitaxy

1986 ◽  
Vol 4 (4) ◽  
pp. 2200-2204 ◽  
Author(s):  
Andrei Szilagyi ◽  
Michael N. Grimbergen
Keyword(s):  
Threading Dislocations

scholarly journals Dislocation Arrangement in a Thick LEO GaN Film on Sapphire

2000 ◽  
Vol 5 (S1) ◽  
pp. 97-103
Author(s):  
Kathleen A. Dunn ◽  
Susan E. Babcock ◽  
Donald S. Stone ◽  
Richard J. Matyi ◽  
Ling Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Burgers Vector ◽  
X Ray ◽  
The Third ◽  
Dislocation Arrangement ◽  
Image Position ◽  
Gan Film

Diffraction-contrast TEM, focused probe electron diffraction, and high-resolution X-ray diffraction were used to characterize the dislocation arrangements in a 16µm thick coalesced GaN film grown by MOVPE LEO. As is commonly observed, the threading dislocations that are duplicated from the template above the window bend toward (0001). At the coalescence plane they bend back to lie along [0001] and thread to the surface. In addition, three other sets of dislocations were observed. The first set consists of a wall of parallel dislocations lying in the coalescence plane and nearly parallel to the substrate, with Burgers vector (b) in the (0001) plane. The second set is comprised of rectangular loops with b = 1/3 [110] (perpendicular to the coalescence boundary) which originate in the coalescence boundary and extend laterally into the film on the (100). The third set of dislocations threads laterally through the film along the [100] bar axis with 1/3<110>-type Burgers vectors These sets result in a dislocation density of ∼109 cm−2. High resolution X-ray reciprocal space maps indicate wing tilt of ∼0.5º.

Impact of open-core threading dislocations on the performance of AlGaN metal-semiconductor-metal photodetectors

2018 ◽  
Vol 123 (16) ◽  
pp. 161551 ◽  
Author(s):  
S. Walde ◽  
M. Brendel ◽  
U. Zeimer ◽  
F. Brunner ◽  
S. Hagedorn ◽  
...  
Keyword(s):  
Threading Dislocations ◽  
Metal Semiconductor Metal ◽  
Open Core
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