Surface Morphology of Gallium Phosphide Deposited by Chemical Beam Epitaxy and Interrupted Cycle Chemical Beam Epitaxy

1993 ◽  
Vol 317 ◽  
Author(s):  
James T. Kelliher ◽  
John T. Thornton ◽  
Phillip E. Russell ◽  
Klaus J. Bachmann
Keyword(s):  
Surface Morphology ◽  
Gallium Phosphide ◽  
Average Height ◽  
Chemical Beam Epitaxy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Flow ◽  
Force Microscopy ◽  
Atomic Force ◽  
Deposition Conditions

ABSTRACTIn this paper, we describe the relation of the surface morphology of GaP grown by chemical beam epitaxy (CBE) and interrupted cycle chemical beam epitaxy (ICCBE) to the deposition conditions on (001) Si. The films were examined with scanning electron Microscopy (SEM) and atomic force Microscopy (AFM). Initial stages of the films grown by CBE using triethylgallium (TEG) and tertiarybutylphosphine (TBP) examined by SEM reveals in addition to GaP nuclei at 10–100 nm scale, whiskers of typically 100 nm diameter at their bases. AFM Measurements yield an average height of these whiskers of 50 nm that self-terminate and are incorporated into the GaP film upon further growth without loss of epitaxy as determined by x-ray diffraction. Nevertheless, the whiskers are a possible source for defects and surface roughness in thicker films. Whisker formation can be suppressed under conditions of ICCBE by the addition of hydrogen flow, sealing the silicon surface by a smooth thin film of GaP.

Biocompatibility Studies of the Nitinol Thin Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C.Z. Dinu ◽  
R. Tanasa ◽  
V.C. Dinca ◽  
A. Barbalat ◽  
C. Grigoriu ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Fibroblast Cell ◽  
Vero Cells ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fetal Bovine ◽  
Fibroblast Cell Lines

AbstractPulsed Laser Deposition method (PLD) was used to grow nitinol (NiTi) thin films with goal of investigating their biocompatibility. High purity Ni and Ti targets were alternatively ablated in vacuum with a laser beam (λ=355 nm, 10 Hz) and the material was collected on room temperature Ti substrates. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and atomic force microscopy analyses have been performed to investigate the chemical composition, crystalline structure and surface morphology of the NiTi films. The nitinol layers biocompatibility has been tested using as a metric the extent to whichthe cells adhereduring the culture period on the surface of NiTi layers deposited on Ti substrates. Vero and fibroblast cell lines dispersed into MEM (Eagle) solution containing 8% fetal bovine serum, at 37° C, were used for tests. Preliminary studies indicate that the interaction at the interface is specifically controlled by the surface morphology, (especially by surface roughness), and by the chemical state of the surface. Cell behavior after contact with NiTi/Ti structure for different intervals (18, 22 and 25 days for the Vero cells, and after 10 and 25 days for fibroblasts) supports the conclusion that NiTi is a very good candidate as a biocompatible material.

Investigation Of Nucleation And Initial Stage Of Gan Growth By Atomic Force Microscopy And X-Ray Diffraction

1997 ◽  
Vol 482 ◽  
Author(s):  
P. W. Yip ◽  
S.-Q. Wang ◽  
A. J. Drehman ◽  
L. D. Zhu ◽  
P. E. Norris
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Morphology ◽  
Deposition Temperature ◽  
Yellow Luminescence ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Initial Stage

AbstractThe nucleation and initial stage of GaN growth on sapphire was investigated by atomic force microscopy, X-ray diffraction and photoluminescence. A 15 to 30 nm thick GaN buffer layer deposited at proper conditions was extremely smooth and nearly amorphous. Proper post deposition annealing resulted in the buffer crystallized. The buffer layer deposition temperature, thickness and annealing time and temperature must be coordinated. Low deposition temperature and/or insufficient annealing of the buffer results in a GaN wafer which has fine spiking surface morphology with an RMS of 3.4 nm for 1.4 μm wafer, strong yellow luminescence and wide xray rocking curve FWHM. High deposition temperature, longer crystallization time, and a low growth rate results in a wafer which exhibits strong band edge luminescence without noticeable yellow luminescence, and a narrow (002) diffraction rocking curve. However, the surface morphology exhibits well developed hexagonal feature with RMS roughness of 14.3 nm for a 570 nm thick layer. X-ray rocking curve analysis revealed buffer crystallization, domain coalescence and alignment process. The FWHM of the ω–scan of GaN (101) diffraction was 1700–2000 arc seconds for 200–1400 nm wafers which indicates that the twist of the domains is not changing much with the growth.

Influence of MeV Gamma Photons on Thermally Stimulated Exoelectron Emission from MgO Films

2021 ◽  
Vol 903 ◽  
pp. 162-167
Author(s):  
Marina Romanova ◽  
Regīna Burve ◽  
Yuri Dekhtyar ◽  
Kristaps Palskis ◽  
Vera Serga
Keyword(s):  
Atomic Force Microscopy ◽  
Radiation Dose ◽  
Surface Morphology ◽  
Percentage Increase ◽  
Exoelectron Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gamma Irradiated

The effect of 6 MeV gamma photons on thermally stimulated exoelectron emission (TSEE) spectra of MgO films was studied. The films were fabricated on Si/SiO2 substrates using the extraction-pyrolytic method. The crystalline structure and surface morphology of the films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). TSEE spectra of MgO films had emission peaks at about 450 oC and 525 oC. The area under the TSEE peaks increased after repeated TSEE measurements. In the case of gamma-irradiated films, the percentage increase in the area depended on the radiation dose, decreasing linearly with an increase in the radiation dose from 0 to 80 Gy. The results suggest that gamma radiation reduced the density of trapped electrons present in the as-grown MgO films or created competing hole traps that inhibited TSEE from the films.

Nanoindention studies of DC sputtered Cu and Cu/Cr thin films

2001 ◽  
Vol 672 ◽  
Author(s):  
G. Wei ◽  
J. Du ◽  
A. Rar ◽  
J. A. Barnard
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Grain Size ◽  
Surface Morphology ◽  
Film Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Grain Size And Orientation

ABSTRACTThe nanoindentation behavior of DC magnetron sputtered 10 nm Cu and 10 nm Cu/2 nm Cr thin films deposited on Si (100) has been studied using a Hysitron nanomechanical system. X- ray diffraction and X-ray reflectivity were used to measure the film structure and film thickness, respectively. The grain size and orientation of Cu and Cu/Cr thin films were measured by TEM. Atomic force microscopy (AFM) was used to evaluate the surface morphology and roughness. At the same load, the nanoindentaion displacement of Cu/Cr is smaller than that for Cu, i.e., the 2nm thick Cr underlayer enhances the hardness of Cu. X-ray, TEM, and AFM results show that the grain size of Cu/Cr (< 15 nm) is actually larger than Cu (∼ 3 nm) indicating that the inverse Hall-Petch relationship may be operative.

SWIFT HEAVY ION INDUCED NANOHILL FORMATION ON THE SURFACE OF GaP

2011 ◽  
Vol 10 (01n02) ◽  
pp. 105-109 ◽  
Author(s):  
R. L. DUBEY ◽  
S. K. DUBEY ◽  
A. D. YADAV ◽  
D. KANJILAL
Keyword(s):  
Atomic Force Microscopy ◽  
Crystallite Size ◽  
Gallium Phosphide ◽  
Phonon Mode ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Swift Heavy Ion

Gallium phosphide ( GaP ) samples were irradiated with swift (100 MeV)56 Fe 9+ ions for various ion fluences varying from 1 × 1011 to 1 × 1014 cm -2. Atomic force microscopy, Raman scattering, and X-ray diffraction techniques have been used to investigate the irradiation effect. Atomic force microscopy studies showed the presence of nanosized hills separated with valleys at the surface of irradiated gallium phosphide. The average diameters of hills were found to be 19.76, 19.81, 20.70, and 22.64 nm for ion fluences 5 × 1012, 1 × 1013, 5 × 1013, and 1 × 1014 cm -2, respectively. Root mean square surface roughness analysis has been used to characterize the nature of the surface under swift heavy ion irradiation. The features observed in the Raman spectra at 402.18 cm-1 and 365.05 cm-1 were assigned to the characteristic first-order longitudinal optical (LO) phonon mode and transverse optical (TO) phonon mode of gallium phosphide, respectively. We have also observed the second-order overtones and combinations of optical modes giving rise to three characteristic peaks in the region between 700 and 800 cm-1. X-ray diffraction technique has been used to determine the crystallite size. The crystallite size was found to decrease with increase in ion fluence.

scholarly journals Electrodeposition from a Graphene Bath: A Sustainable Copper Composite Alloy in a Graphene Matrix

2020 ◽  
Vol 5 (1) ◽  
pp. 9
Author(s):  
Hayley Richardson ◽  
Charles Bopp ◽  
Bao Ha ◽  
Reeba Thomas ◽  
Kalathur S.V. Santhanam
Keyword(s):  
Surface Morphology ◽  
Graphene Quantum Dots ◽  
X Ray Diffraction ◽  
Brass Alloy ◽  
Current Time ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Copper Composite ◽  
Nucleation And Growth Mechanism

The leaching effect of metals has led to the introduction of government regulations for the safety of the environment and humans. This has led to the search for new alloys with long-lasting sustainability. Herein, we wish to report a new brass alloy containing carbon with a remarkable sustainability produced by electrodeposition from a graphene quantum dots bath. The electrochemical measurements were carried out using cyclic voltammetry, potentiodynamic analysis, and Tafel measurements, and the deposits were characterized by X-ray fluorescence spectroscopy (XRF), Raman imaging, X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) to understand the surface morphology and elemental compositions. The current–time transients in the potential-step electrolysis were used to investigate the nucleation and growth mechanism. The smooth and compact deposit obtained at −0.60 V showed a composition of Cu = 24.33 wt %; Zn = 0.089 wt %; and C = 75.57 wt %. The SEM and energy dispersion X-ray analysis revealed a surface morphology with a uniform distribution of the particles and the presence of Cu, Zn, and C. The corrosion density of the material is very much lower than that of conventional brass, suggesting a higher sustainability.

Correlation between Extended Defects and Surface Morphology in MBE Grown InAs/GaAs Heterostructures

1995 ◽  
Vol 399 ◽  
Author(s):  
M.R. Bruni ◽  
G. Padeletti ◽  
M.G. Simeone ◽  
L. Francesio ◽  
P. Franzosi ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Growth Temperature ◽  
Crystal Defects ◽  
Extended Defects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron

ABSTRACTInAs single layers were grown by Molecular Beam Epitaxy on nominally (001) oriented GaAs substrates at growth temperatures ranging from 350 °C to 500 °C and thicknesses between 1 nm and 6 μm. A systematic study of the influence of growth temperature and thickness on crystal defects and surface morphology is discussed by comparing High Resolution X-Ray Diffraction, Transmission Electron Microscopy and Atomic Force Microscopy investigations.Surface hexagonal shaped holes were observed to develop at the lowest temperatures starting from an heterolayer thickness of 50 nm. Both misfit and threading dislocations were revealed; moreover the correlation between hexagonal shaped surface holes and mixed dislocations, with the component of the Burgers vector (b) along the growth axis larger than the minimum interatomic distance, is discussed. The holes increase in size and decrease in density by increasing the layer thickness. An almost complete surface planarization is observed at a thickness of 6 μm by increasing the growth temperature up to 500 °C.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

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