Raman Scattering and X-Ray Diffraction Studies of Gallium Nitride Films Grown on (100) Gallium Arsenide

1994 ◽  
Vol 339 ◽  
Author(s):  
S. W. Brown ◽  
S. C. Rand ◽  
C.-H. Hong ◽  
D. Pavlidis
Keyword(s):  
Gallium Arsenide ◽  
Gallium Nitride ◽  
Raman Scattering ◽  
Raman Spectra ◽  
Phonon Mode ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray ◽  
Different Temperatures ◽  
Cubic Gan

ABSTRACTRaman spectroscopy and x-ray diffraction are used to characterize Gallium Nitride (GaN) films grown on (100) Gallium Arsenide (GaAs) substrates. Reflection X-ray diffraction data from (200) planes of GaAs and cubic GaN are presented. The linewidth of the cubic GaN diffraction peak is shown to be a strong function of the growth temperature. Raman spectra are presented for a series of samples grown at different temperatures. Raman scattering is characterized by strong peaks at 560 cm-1 and at 736 cm-1, corresponding to TO and LO phonon modes of cubic GaN, respectively. An additional, unexplained feature at 768 cm-1 is clearly observed in Raman spectra of c-GaN samples grown at lower temperatures. The polarization dependence of the intensity of the GaN LO phonon mode is presented and compared with the GaAs LO phonon mode to establish the relative orientation of the c-GaN epitaxy on GaAs.

Effects of Helium Ion Implantation on the Optical and Crystal Properties of GaAs

1989 ◽  
Vol 147 ◽  
Author(s):  
R. C. Bowman ◽  
P. M. Adams ◽  
J. F. Knudsen ◽  
S. C. Moss ◽  
P. A. Dafesh ◽  
...  
Keyword(s):  
Electron Beam ◽  
Raman Scattering ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
Double Crystal ◽  
Damage Behavior ◽  
X Ray ◽  
Crystal Properties ◽  
Helium Ion ◽  
Different Levels

AbstractThe damage to GaAs crystals caused by helium ion implants has been monitored by changes in the Raman scattering phonon modes, double-crystal x-ray diffraction rocking curves, photoreflectance (PR), and electron beam electroreflectance (EBER) band edge transitions. As the implanted helium ion dose was increased, the various techniques revealed threshold damage behavior at very different levels. Although PR and EBER were the most sensitive to the defects created at the lowest ion doses, all techniques indicated substantial disorder for implants greater than 1014 ions/cm2.

scholarly journals Growth of Oriented Thick Films of Gallium Nitride from the Melt

1999 ◽  
Vol 4 (S1) ◽  
pp. 227-232 ◽  
Author(s):  
Jeffrey S. Dyck ◽  
Kathleen Kash ◽  
Michael T. Grossner ◽  
Cliff C. Hayman ◽  
Alberto Argoitia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gallium Nitride ◽  
Microwave Plasma ◽  
Thick Films ◽  
Attractive Alternative ◽  
Plasma Synthesis ◽  
Atomic Nitrogen ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray

While significant strides have been made in the optimization of GaN-based devices on foreign substrates, a more attractive alternative would be homoepitaxy on GaN substrates. The primary motivation of this work is to explore the growth of thick films of GaN from the melt for the ultimate use as substrate material. We have previously demonstrated the synthesis of polycrystalline, wurtzitic gallium nitride and indium nitride by saturating gallium metal and indium metal with atomic nitrogen from a microwave plasma source. Plasma synthesis avoids the high equilibrium pressures required when molecular nitrogen is used as the nitrogen source. Here we report the growth of thick oriented GaN layers using the same technique by the introduction of (0001) sapphire into the melt to serve as a substrate. The mechanism of this growth is not established, but may involve transport of the metal as a liquid film onto the sapphire and subsequent reaction with atomic nitrogen. The films were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. X-ray diffraction showed that the GaN films were oriented with their c-axes parallel to the sapphire c-axis. The TEM analysis confirmed the orientation and revealed a dislocation density of approximately 1010 cm−2. The E2 Raman active phonon modes were observed in the GaN films.

Growth of Oriented Thick Films of Gallium Nitride From the Melt

1998 ◽  
Vol 537 ◽  
Author(s):  
Jeffrey S. Dyck ◽  
Kathleen Kash ◽  
Michael T. Grossner ◽  
Cliff C. Hayman ◽  
Alberto Argoitia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gallium Nitride ◽  
Microwave Plasma ◽  
Thick Films ◽  
Attractive Alternative ◽  
Plasma Synthesis ◽  
Atomic Nitrogen ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray

AbstractWhile significant strides have been made in the optimization of GaN-based devices on foreign substrates, a more attractive alternative would be homoepitaxy on GaN substrates. The primary motivation of this work is to explore the growth of thick films of GaN from the melt for the ultimate use as substrate material. We have previously demonstrated the synthesis of polycrystalline, wurtzitic gallium nitride and indium nitride by saturating gallium metal and indium metal with atomic nitrogen from a microwave plasma source. Plasma synthesis avoids the high equilibrium pressures required when molecular nitrogen is used as the nitrogen source. Here we report the growth of thick oriented GaN layers using the same technique by the introduction of (0001) sapphire into the melt to serve as a substrate. The mechanism of this growth is not established, but may involve transport of the metal as a liquid film onto the sapphire and subsequent reaction with atomic nitrogen. The films were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. X-ray diffraction showed that the GaN films were oriented with their c-axes parallel to the sapphire c-axis. The TEM analysis confirmed the orientation and revealed a dislocation density of approximately 1010 cm-2. The E2 Raman active phonon modes were observed in the GaN films.

RAMAN SCATTERING AND X-RAY DIFFRACTION CHARACTERIZATION OF AMORPHOUS SEMICONDUCTOR MULTILAYER INTERFACES

1985 ◽  
Vol 56 ◽  
Author(s):  
J. GONZALEZ ◽  
D.D. ALLRED ◽  
O.V. NGUYEN ◽  
D. MARTIN ◽  
D. PAWLIK
Keyword(s):  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Raman Spectra ◽  
Amorphous Semiconductor ◽  
Chemical Bonds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sharp Interfaces ◽  
Deposition Techniques

AbstractIn the present study, Raman spectroscopy (RS) and x-ray diffraction have been used to characterize semiconductor multilayer interfaces. A model for Raman spectra of multilayers is developed and applied to the specific case of the interfaces of a-Si/a-Ge multilayers. Quantification of the ‘blurring’ of interfaces is possible because RS is capable of directly ‘counting’ the total number of chemical bonds of a given type in the film. Multilayers, prepared by various deposition techniques, are compared. Several a-Si/a-Ge multilayers deposited by UHV evaporation (MBD) exhibit exceptionally sharp interfaces (intermixing width <l.0Å) and regular periodicities.

Temperature Dependent Raman Scattering and Dielectric Permittivity Measurements of Pb1−x Srx TiO3 Films

2003 ◽  
Vol 784 ◽  
Author(s):  
V. M. Naik ◽  
M. Smith ◽  
H. Dai ◽  
P. Talagala ◽  
R. Naik ◽  
...  
Keyword(s):  
Phase Transition ◽  
Dielectric Permittivity ◽  
Raman Spectra ◽  
Tetragonal Phase ◽  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray ◽  
Permittivity Measurements

ABSTRACTPb1-x Srx TiO3 (x = 0 to 1.0) films of thickness ∼ 4 μ m have been prepared on sapphire and Pt substrates by metalorganic decomposition (MOD) method. X-ray diffraction results show that the films are polycrystalline with a perovskite tetragonal phase at room temperature for x < 0.5 and a cubic phase for x > 0.5. Room temperature Raman spectra show a systematic variation of lattice vibrational modes with x. The most notable changes in the Raman spectra with x are the decrease in the splitting of A1(3TO) and E(3TO) modes and the disappearance of E(3TO) mode at x ∼ 0.6. Although the x-ray diffraction peaks for films with x > 0.5 show a cubic phase at room temperature, the Raman spectra show the characteristic phonon modes of a tetragonal phase even at x = 0.7. The dielectric permittivity versus temperature measurements for films with x ≤ 0.7 show a broad dielectric anomaly corresponding to a diffuse ferroelectric to paraelectric phase transition. The phase transition temperature (Tc) values are consistently lower than the corresponding bulk ceramic alloys. Furthermore, Tc are also determined by monitoring the temperature dependence of the splitting between E(3TO) and A1(3TO) phonon modes in the Raman spectra of Pb1-x Srx TiO3 films for x ≤ 0.6. There has been good agreement between the two methods.

Micro-Raman Scattering Properties of Highly Oriented AlN Films

1998 ◽  
Vol 12 (19) ◽  
pp. 1963-1974 ◽  
Author(s):  
Ming S. Liu ◽  
K. W. Nugent ◽  
S. Prawer ◽  
L. A. Bursill ◽  
J. L. Peng ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Raman Scattering ◽  
Film Plane ◽  
Phonon Confinement ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray ◽  
Transmission Electron ◽  
Scattering Geometry ◽  
Confinement Model

Micro-Raman scattering by highly oriented crystalline aluminum nitride has been measured. Phonon modes in AlN were identified in different scattering geometry configurations and scattering polarizations. The phonon modes revealed that aluminum nitride films are highly oriented with the wurtzite c-axis direction normal to the film plane. The Raman scattering modes are broadened and shifted due to grain boundaries and other defects in the films. The defect scattering was analysed using the phonon confinement model. These results were compared with results obtained from X-ray diffraction powder patterns and high-resolution transmission electron microscopy.

Comparative Study of 3C-GaN Grown on Semi-Insulating 3C-SiC/Si(100) Substrates

2009 ◽  
Vol 615-617 ◽  
pp. 943-946 ◽  
Author(s):  
Elena Tschumak ◽  
Katja Tonisch ◽  
Jörg Pezoldt ◽  
Donat J. As
Keyword(s):  
Residual Stress ◽  
Gallium Nitride ◽  
High Resolution ◽  
Silicon Substrates ◽  
Full Width ◽  
Half Maximum ◽  
X Ray Diffraction ◽  
Grown Layer ◽  
X Ray ◽  
Cubic Gan

Cubic gallium nitride epitaxial layers grown on differently carbonized silicon substrates were studied by high resolution X-ray diffraction. In the case of cubic GaN layers with equal layer thickness an improvement of the layer quality in terms of full width of the half maximum can be achieved by using higher carbonization temperatures. The higher crystalline quality led to an in¬crease of the residual stress in the grown layer. An increase in the thickness of the cubic Gallium Nitride allows to improve the crystallinity and to reduce the residual stress.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

scholarly journals Hydrothermal Ageing and Its Effect on Fracture Load of Zirconia Dental Implants

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3103
Author(s):  
Laurent Gremillard ◽  
Agnès Mattlet ◽  
Alexandre Mathevon ◽  
Damien Fabrègue ◽  
Bruno Zberg ◽  
...  
Keyword(s):  
Dental Implants ◽  
Fracture Load ◽  
Accelerated Ageing ◽  
Dental Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dental Restorations ◽  
Different Temperatures ◽  
Mechanical Performances ◽  
Kinetics Of

Due to growing demand for metal-free dental restorations, dental ceramics, especially dental zirconia, represent an increasing share of the dental implants market. They may offer mechanical performances of the same range as titanium ones. However, their use is still restricted by a lack of confidence in their durability and, in particular, in their ability to resist hydrothermal ageing. In the present study, the ageing kinetics of commercial zirconia dental implants are characterized by X-ray diffraction after accelerated ageing in an autoclave at different temperatures, enabling their extrapolation to body temperature. Measurements of the fracture loads show no effect of hydrothermal ageing even after ageing treatments simulated a 90-year implantation.

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