A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

1999 ◽  
Vol 13 (09n10) ◽  
pp. 991-996
Author(s):  
M. Salvato ◽  
C. Attanasio ◽  
G. Carbone ◽  
T. Di Luccio ◽  
S. L. Prischepa ◽  
...  

High temperature superconducting multilayers have been obtained depositing Bi2Sr2CuO6+δ(2201) and ACuO2 layers, where A is Ca or Sr, by Molecular Beam Epitaxy (MBE) on MgO and SrTiO3 substrates. The samples, formed by a sequence of 2201/ACuO2 bilayers, have different thickness of ACuO2 layers while the thickness of the 2201 layers is kept constant. The surface structure of each layer has been monitored by in situ Reflection High Energy Electron Diffraction (RHEED) analysis which has confirmed a 2D nucleation growth. X-ray diffraction (XRD) analysis has been used to confirm that the layered structure has been obtained. Moreover, one-dimensional X-ray kinematic diffraction model has been developed to interpret the experimental data and to estimate the period of the multilayers. Resistive measurements have shown that the electrical properties of the samples strongly depend on the thickness of the ACuO2 layers.


MRS Advances ◽  
2017 ◽  
Vol 2 (3) ◽  
pp. 189-194
Author(s):  
Franck Natali ◽  
Joe Trodahl ◽  
Stéphane Vézian ◽  
Antoine Traverson ◽  
Benjamin Damilano ◽  
...  

ABSTRACTGdN/SmN based superlattices have been grown by molecular beam epitaxy. In-situ reflection high energy electron diffraction was used to evaluate the evolution of the epitaxial growth and the structural properties were assessed by ex-situ X-ray diffraction. Hall Effect and resistivity measurements as a function of the temperature establish that the superlattices are heavily n-type doped semiconductors and the electrical conduction resides in both REN layers, SmN and GdN.


MRS Advances ◽  
2020 ◽  
Vol 5 (29-30) ◽  
pp. 1529-1535 ◽  
Author(s):  
Rijie Zhao ◽  
Jianrong Gao ◽  
Yang Ren

AbstractMelting, solidification and solid-state transformation of the intermetallic Ni3Sn compound were investigated in situ using synchrotron high-energy X-ray diffraction. It was observed that the compound undergoes a hexagonal to cubic transition before melting. In solidification, a disordered cubic phase crystallizes from the liquid at a large undercooling but it is reordered prior to bulk solidification. In melting and solidification, forced or natural flows are active bringing about significant changes of crystal orientations. These in situ observations provided insights into phase transformations of Ni3Sn at elevated temperatures and their roles in formation of metastable microstructure consisting of coarse grains and subgrains.


2005 ◽  
Vol 357 (1-2) ◽  
pp. 165-169 ◽  
Author(s):  
Vladimir M. Kaganer ◽  
Wolfgang Braun ◽  
Bernd Jenichen ◽  
Klaus H. Ploog

2002 ◽  
Vol 743 ◽  
Author(s):  
N. Onojima ◽  
J. Suda ◽  
H. Matsunami

ABSTRACTAluminum nitride (AlN) has been grown on 6H-silicon carbide (SiC) substrates with the non-polar (1120) face using rf plasma-assisted molecular-beam epitaxy (rf-MBE). Reflection high-energy electron diffraction (RHEED) revealed that AlN and 6H-SiC (1120) had an exact epitaxial relationship, i.e., [1120]AlN|[1120]SiC and [0001]AlN∥[0001]SiC. From the result of microscopic Raman scattering spectroscopy, the stacking structure of the AlN epitaxial layer was suggested to be a 2H structure, not a 6H structure. A directly grown AlN layer and layer with AlN low-temperature (LT) buffer layer were investigated based on atomic force microscopy (AFM) and X-ray diffraction (XRD).


2009 ◽  
Vol 1198 ◽  
Author(s):  
Costel Constantin ◽  
Kangkang Wang ◽  
Abhijit Chinchore ◽  
Han-Jong Chia ◽  
John Markert ◽  
...  

AbstractFe0.1Sc0.9N with a thickness of ˜ 380 nm was grown on top of a ScN(001) buffer layer of ˜ 50 nm, grown on MgO(001) substrate by radio-frequency N-plasma molecular beam epitaxy (rf-MBE). The buffer layer was grown at TS ˜ 800 oC, whereas the Fe0.1Sc0.9N film was grown at TS ˜ 420 oC. In-situ reflection high-energy electron diffraction measurements show that the Fe0.1Sc0.9N film growth starts with a combination of spotty and streaky pattern [indicative of a combination of smooth and rough surface]. After ˜ 10 minutes of growth, the pattern converts to a spotty one [indicative of a rough surface]. Towards the end of the Fe0.1Sc0.9N film growth, the spotty patterns transform into even spottier, but also ring-like indicating a polycrystalline behavior. Superconducting quantum interference device magnetic measurements show a ferromagnetic to paramagnetic transition of TC ˜ 370 – 380 K. We calculated a magnetic moment per atom of μ(Fe0.1Sc0.9N) = 0.037 Bohr magneton/ Mn-atom. Based on the carrier concentration measurements (nS(Fe0.1Sc0.9N) = 2.086 × 1019 /cm3), we find that iron behaves as an acceptor. Comparisons are made with similar MnScN (001)/ScN(001)/MgO(001) system.


1992 ◽  
Vol 281 ◽  
Author(s):  
T. P. Chin ◽  
J. C. P. Chang ◽  
K. L. Kavanagh ◽  
C. W. Tu ◽  
P. D. Kirchner ◽  
...  

ABSTRACTInxGa1−xP(x>0.27) grown on a GaP substrate has a large direct-bandgap, which is suitable for yellow light emission on a transparent substrate. Because of the large lattice mismatch, usually a thick (10–20 μm) graded buffer layer was required to reduce the threading dislocation density. In this work we report that a thin (1.2 μm for x≃0.35), linearly graded buffer layer can filter out dislocations effectively. The structures were grown by gas-source molecular beam epitaxy. Reflection high-energy electron diffraction (RHEED) intensity oscillations and X-ray double-crystal diffraction were used to control and determine the composition, respectively. Threading dislocations are well confined in the buffer layer, as shown under transmission electron microscopy. Dislocation loops injected into the substrate were observed, similar to those observed in the Six Ge1−x/Si system. X-ray analysis also shows that the 3% mismatched buffer layer is fully relaxed. This relaxed buffer layer then can serve as a substrate for further growth. Homojunction and heterojunction light emitting diodes were fabricated to demonstrate the material quality.


1995 ◽  
Vol 399 ◽  
Author(s):  
A. Gray ◽  
N.K. Dhar ◽  
W. Clark ◽  
P. Charlton ◽  
J.H. Dinan ◽  
...  

ABSTRACTX-ray diffraction spectra of CdTe epilayers grown with and without ZnTe buffer layers on <211> Si substrates by molecular beam epitaxy consist of 422 and 331 reflections. We interpret these as evidence for the existence of twins within the volume of a <211> oriented epilayer and show that twin volume is dependent on the ZnTe buffer layer and substrate misorientation.


1995 ◽  
Vol 10 (8) ◽  
pp. 1942-1952 ◽  
Author(s):  
A. Guivarc'h ◽  
A. Le Corre ◽  
P. Auvray ◽  
B. Guenais ◽  
J. Caulet ◽  
...  

This paper deals with the growth by molecular beam epitaxy of semimetallic (rare-earth group V element) compounds on III-V semiconductors. Results are presented, first on the Er-Ga-As and Er-Ga-Sb ternary phase diagrams, second on the lattice-mismatched ErAs/GaAs (δa ≈ +1.6%), YbAs/GaAs (δa/a = +0.8%), and ErSb/GaSb (δa/a ≈ +0.2%) heterostructures, and third on the lattice-matched Sc0.3Er0.7As/GaAs and Sc0.2Yb0.8As/GaAs systems (δa/a < 0.05%). Finally the growth of YbSb2 on GaSb(001) is reported. The studies made in situ by reflection high-energy electron diffraction (RHEED) and x-ray photoelectron diffraction and ex situ by x-ray diffraction, transmission electron microscopy, He+ Rutherford backscattering, and photoelectron spectroscopy are presented. We discuss the atomic registry of the epitaxial layers with respect to the substrates, the appearance of a mosaic effect in lattice-mismatched structures, and the optical and electrical properties of the semimetallic films. The problems encountered for III-V overgrowth on these compounds (lack of wetting and symmetry-related defects) are commented on, and we underline the interest of compounds as YbSb2 which avoid the appearance of inversion defects in the GaSb overlayers.


Sign in / Sign up

Export Citation Format

Share Document