MBE Growth and Characterization of Device-Quality Thick InN Epilayers; Comparison between N-polarity and In-polarity Growth Processes

2004 ◽  
Vol 831 ◽  
Author(s):  
Akihiko Yoshikawa ◽  
Yoshihiro Ishitani ◽  
Song-Bek Che ◽  
Ke Xu ◽  
Xinqiang Wang ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Hall Mobility ◽  
Room Temperature ◽  
In Situ Monitoring ◽  
Mbe Growth ◽  
X Ray ◽  
Step Flow ◽  
Rich Condition

ABSTRACTEpitaxy of InN films with N-polarity and In-polarity was investigated by RF-MBE with several in-situ monitoring/controlling systems. It was found that the epitaxy temperature for N-polarity growth could be as high as 600 °C and this was about 100 deg higher than that for In-polarity case. This temperature difference in two polarities drastically affected not only the growth behaviors but also the properties of InN epilayers, i.e. N-polarity growth was preferable in both view-points. The step-flow-like surface morphology was achieved for the InN films grown with N-polarity at 580 °C. The FWHMs of X-ray rocking curves for InN (002) and (102) of 5–8 μm-thick InN films grown in N-polarity were about 200–350 and 650–950 arcsec, respectively. The highest Hall mobility was above 2000 cm2/V·s with a background carrier concentration of 1–2×1018 cm−3 at room temperature. For both polarity films, N-rich condition was necessary for the stable InN growth to obtain 5–8 μm-thick InN films.

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

Photoreflectance Characterization of the Semi-Insulating InP Substrate Interface with InGaAs and InAlAs Epilayers

1992 ◽  
Vol 281 ◽  
Author(s):  
Weimin Zhou ◽  
H. Shen ◽  
J. Pamulapati ◽  
M. Dutta ◽  
B. R. Bennett ◽  
...  
Keyword(s):  
Electron Transition ◽  
In Situ Monitoring ◽  
Signal Phase ◽  
Mbe Growth ◽  
Substrate Interface ◽  
Inp Substrate ◽  
Excitonic Transition ◽  
Inp Substrates

ABSTRACTPhotoreflectance (PR) has been performed on a series of undoped and n-type, InGaAs and InAlAs molecular beam epitaxy (MBE) grown layers with different In mole fractions, and epilayer thicknesses on Fe-doped semi-insulating (SI)-InP substrates. From investigations of the temperature dependence, time constant dependence and an additional cw light beam intensity dependence, three substrate peaks are identified as an excitonic transition from the substrate, a free electron transition near the interface which gives a Franz-Keldysh oscillation (KFO), and a transition from the spin-orbit split-off valence band. The results are indicative of a redistribution of charge near the substrate interface in the process of MBE growth; the associated PR signal (phase) could be used for in-situ monitoring of epilayer growth on SI-InP wafers.

scholarly journals Lactide polymerization with iron alkoxide complexes

2015 ◽  
Vol 93 (6) ◽  
pp. 594-601 ◽  
Author(s):  
Arek Keuchguerian ◽  
Berline Mougang-Soume ◽  
Frank Schaper ◽  
Davit Zargarian
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Side Reactions ◽  
X Ray Diffraction ◽  
Iron Cluster ◽  
X Ray ◽  
H Nmr ◽  
Exchange Product

This report presents the results of a study on the preparation of iron alkoxide complexes chelated by diiminopyridine ligands and their role in the room temperature polymerization of rac-lactide. Reaction of N,N′-(p-R-C6H4CH2)2-diiminopyridines (R = H (1), F (2)) with FeX2 (X = Cl, Br) yielded the homoleptic complexes [(1)2Fe][FeX4] or [(2)2Fe][FeX4], respectively. Treating the latter with Na[BPh4] afforded the anion exchange product [(2)2Fe][BPh4]2, which was characterized by 1H NMR and absorption spectroscopy, combustion analysis, and single crystal X-ray diffraction. Various attempts to grow crystals of [(1)2Fe][FeX4] and [(2)2Fe][FeX4] culminated in the isolation of single crystals of [(2)2Fe][Cl6Fe2O] that was characterized by X-ray diffraction. Attempted synthesis of well-defined, mononuclear alkoxide derivatives from [(1)2Fe]2+ or [(2)2Fe]2+ gave mostly intractable products, but in one case we obtained the crystallographically characterized sodium iron cluster Na4Fe2(OC6H4F)8(THF)2. An aryloxide derivative proved accessible by reaction of NaOC6H4F with the mono-ligand precursor LFeCl2 (L = N,N′-dimesityl-diiminopyridine), but characterization of LFe(OC6H4F)2 was limited to a single crystal X-ray diffraction analysis, owing to unsuccessful attempts at isolating pure samples. The difficulties encountered in the isolation of pure alkoxide derivatives prompted us to use in-situ generated LFe(OEt)2 for studying the polymerization of rac-lactide. This system was found to be moderately active at room temperature and with a slight preference for the formation of a heterotactic polymer (Pr = 0.54–0.65). Large polydispersities of 1.5–2.0 indicated the presence of transesterification side-reactions, which were confirmed by the presence of peaks with m/z = n 144 + M(EtOH) + M(Na+) and m/z = (n + 0.5) 144 + M(EtOH) + M(Na+) in MALDI-MS.

Phase Evolutions in the Metallic Precursors of the Ternary Copper-Indium-Gallium System

2013 ◽  
Vol 774-776 ◽  
pp. 974-980
Author(s):  
Jian Wang ◽  
Jie Zhu
Keyword(s):  
Surface Morphology ◽  
Room Temperature ◽  
Intermetallic Phase ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Indium ◽  
Rich Condition ◽  
Indium Gallium ◽  
Copper Indium Gallium

Two types of metallic precursors used for the growth of Cu (In,Ga)Se2were deposited from a single CuInGa ternary target and binary alloy CuGa and CuIn targets, respectively. Phase evolutions in the precursors of the ternary copper-indium-gallium system were investigated over the temperature range from room temperature to 500°C. Grazing incidence X-ray diffraction (GIXRD) and scanning electron microscopy (SEM) were applied to characterize evolution of phases and surface morphology in the precursor layers. With annealing temperatures increased, phase evolutions of Cu9Ga4, Cu11In9, Cu16In9and CuIn were observed. Surface morphology of the two types of precursors changed significantly, which could support the phase evolutions in the ternary Cu-In-Ga system for reactive annealing processes. The existence of the final Cu11In9phase, which is the most favorable intermetallic phase for the formation of CuInSe2and Cu (In,Ga)Se2thin films, may be transformed by a speculated peritectoid reaction of In and Cu16In9to Cu11In9under In-rich condition.

Controlled Growth and Characterization of Non-tapered InN Nanowires on Si(111) Substrates by Molecular Beam Epitaxy

2009 ◽  
Vol 1178 ◽  
Author(s):  
Yi-Lu Chang ◽  
Arya Fatehi ◽  
Feng Li ◽  
Zetian Mi
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Room Temperature ◽  
Molecular Beam ◽  
Stacking Faults ◽  
Seeding Layer ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial

AbstractWe have performed a detailed investigation of the molecular beam epitaxial (MBE) growth and characterization of InN nanowires spontaneously formed on Si(111) substrates under nitrogen rich conditions. Controlled epitaxial growth of InN nanowires (NWs) has been demonstrated by using an in situ deposited thin (˜ 0.5 nm) In seeding layer prior to the initiation of growth. By applying this technique, we have achieved non-tapered epitaxial InN NWs that are relatively free of dislocations and stacking faults. Such InN NW ensembles display strong photoluminescence (PL) at room temperature and considerably reduced spectral broadening, with very narrow spectral linewidths of 22 and 40 meV at 77 K and 300 K, respectively.

MBE Growth and Characterization of Zns/Gan Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
E. C. Piquette ◽  
Z. Z. Bandić ◽  
J. O. McCaldin ◽  
T. C. McGill
Keyword(s):  
Nitrogen Plasma ◽  
Carbon Surface ◽  
X Ray Diffraction ◽  
Lower Growth ◽  
Mbe Growth ◽  
X Ray ◽  
Donor Acceptor ◽  
Free Films

ABSTRACTHeterostructures involving ZnS/GaN show promise for the injection of holes from p-GaN into n-ZnS. This combination could result in multi-color electroluminescent displays. We have grown single crystal ZnS on GaN and sapphire (0001) by MBE using elemental sources. The ZnS was grown at temperatures from 150°C–400°C, with beam flux equivalent pressures of (0.3 – 2.0) × 10−7 torr. Growth rates of up to 0.4 μm per hour were observed for the lower growth temperatures, with rapidly diminishing rates for temperatures above 350μC. The GaN substrate consisted of a 3 μm epilayer grown on sapphire by MOCVD. XPS analysis revealed the presence of carbon surface contamination on the GaN, which was removed by in situ exposure to an RF nitrogen plasma. RHEED observations indicate that the zincblende ZnS layers commonly contain (111) twins, although twin free films may be grown at a high substrate temperature. The samples were characterized using photoluminescence and X-ray diffraction. X-ray peaks typically had FWHM of 400 arcsec for ω/2θ scans, and somewhat worse for ω scans. Photoluminescence spectra of the ZnS films doped with Ag and Al demonstrated the well known blue donor acceptor transition at 440 nm.

In Situ Monitoring of MBE Growth of a Single Self-Catalyzed GaAs Nanowire by X-ray Diffraction

2021 ◽  
Author(s):  
Seyed Mohammad Mostafavi Kashani ◽  
Vladimir G. Dubrovskii ◽  
Tilo Baumbach ◽  
Ullrich Pietsch
Keyword(s):  
In Situ Monitoring ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
X Ray ◽  
Gaas Nanowire

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Growth of Epitaxial IrSi3 Layers on Si(111)

1989 ◽  
Vol 160 ◽  
Author(s):  
T. L. Lin ◽  
C. W. Nieh
Keyword(s):  
Surface Morphology ◽  
Molecular Beam ◽  
Solid Phase ◽  
Single Mode ◽  
Growth Conditions ◽  
Tem Analysis ◽  
Mbe Growth ◽  
Good Surface ◽  
Transmission Electron

AbstractEpitaxial IrSi3 films have been grown on Si (111) by molecular beam epitaxy (MBE) at temperatures ranging from 630 to 800 °C and by solid phase epitaxy (SPE) at 500 °C. Good surface morphology was observed for IrSi3 layers grown by MBE at temperatures below 680 °C, and an increasing tendency to form islands is noted in samples grown at higher temperatures. Transmission electron microscopy (TEM) analysis reveals that the IrSi3 layers grow epitaxially on Si(111) with three epitaxial modes depending on the growth conditions. For IrSi3 layers grown by MBE at 630 °C, two epitaxial modes were observed with ~ 50% area coverage for each mode. Single mode epitaxial growth was achieved at a higher MBE growth temperature, but with island formation in the IrSi3 layer. A template technique was used with MBE to improve the IrSi3 surface morphology at higher growth temperatures. Furthermore, single-crystal IrSi3 was grown on Si(111) at 500 °C by SPE, with annealing performed in-situ in a TEM chamber.

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