Structural Changes in a-Si:H Films Deposited on the Edge of Crystallinity

AbstractUsing infrared, H evolution and x-ray diffraction (XRD), the structure of high H dilution, glow discharge deposited a-Si:H films ‘on the edge of crystallinity’ is examined. From the Si-H wag mode peak frequency and the XRD results, we postulate the existence of very small Si crystallites contained within the as-grown amorphous matrix, with the vast majority of the bonded H located on these crystallite surfaces. Upon annealing at ramp rates of 8-15°C/min, a H evolution peak at ~400°C appears, and film crystallization is observed at temperatures as low as 500°C, both of which are far below those observed for a-Si:H films grown without H dilution using similar rates. While the crystallite volume fraction is too small to be detected by XRD in the as-grown films, these crystallites enable the crystallization of the remainder of the amorphous matrix upon moderate annealing, thus explaining the existence of the low temperature H evolution peak.

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An X-Ray diffraction analysis of low temperature structural changes in the myelin lattice

Cryobiology ◽

10.1016/0011-2240(75)90061-9 ◽

1975 ◽

Vol 12 (6) ◽

pp. 555-556

Author(s):

M.J. Costello ◽

H. Bank

Keyword(s):

Low Temperature ◽

Diffraction Analysis ◽

Structural Changes ◽

X Ray Diffraction ◽

X Ray

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Hardness evolution of Al–Cr–N coatings under thermal load

Journal of Materials Research ◽

10.1557/jmr.2008.0366 ◽

2008 ◽

Vol 23 (11) ◽

pp. 2880-2885 ◽

Cited By ~ 32

Author(s):

Herbert Willmann ◽

Paul H. Mayrhofer ◽

Lars Hultman ◽

Christian Mitterer

Keyword(s):

Thermal Load ◽

Structural Changes ◽

Single Phase ◽

Volume Fraction ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Al Content ◽

Annealing Temperatures ◽

Transmission Electron

Microstructure and hardness evolution of arc-evaporated single-phase cubic Al0.56Cr0.44N and Al0.68Cr0.32N coatings have been investigated after thermal treatment in Ar atmosphere. Based on a combination of differential scanning calorimetry and x-ray diffraction studies, we can conclude that Al0.56Cr0.44N undergoes only small structural changes without any decomposition for annealing temperatures Ta ⩽ 900 °C. Consequently, the hardness decreases only marginally from the as-deposited value of 30.0 ± 1.1 GPa to 29.4 ± 0.9 GPa with Ta increasing to 900 °C, respectively. The film with higher Al content (Al0.68Cr0.32N) exhibits formation of hexagonal (h) AlN at Ta ⩾ 700 °C, which occurs preferably at grain boundaries as identified by analytical transmission electron microscopy. Hence, the hardness increases from the as-deposited value of 30.1 ± 1.3 GPa to 31.6 ± 1.4 GPa with Ta = 725 °C. At higher temperatures, where the size and volume fraction of the h-AlN phase increases, the hardness decreases to 27.5 ± 1.0 GPa with Ta = 900 °C.

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Growth and Properties of Lattice Matched GaAsSbN Epilayer on GaAs for Solar Cell Applications

MRS Proceedings ◽

10.1557/proc-0891-ee10-36 ◽

2005 ◽

Vol 891 ◽

Cited By ~ 6

Author(s):

Sudhakar Bharatan ◽

Shanthi Iyer ◽

Kevin Matney ◽

Ward J. Collis ◽

Kalyan Nunna ◽

...

Keyword(s):

Low Temperature ◽

Structural Changes ◽

Ex Situ ◽

Rf Plasma ◽

X Ray Diffraction ◽

X Ray ◽

Peak Energy ◽

Localized Excitons ◽

Matched Layers ◽

Lattice Matched

ABSTRACTIn this work, the growth and characterization of GaAsSbN epilayers nearly lattice matched to GaAs, grown in an elemental solid source molecular beam epitaxy (MBE) system with a RF plasma nitrogen source, are discussed. The Sb and N compositions of the nearly lattice matched layers are 2.6% and 6.8%, respectively, as determined by high resolution x-ray diffraction (HRXRD) and secondary ion mass spectroscopy (SIMS) analysis. The layers are found to be fully strained as evidenced by the presence of Pendellosung fringes on the x-ray diffraction spectra.Effects of in-situ and ex-situ annealing on the low temperature photoluminescence (PL) characteristics are discussed. The 10 K PL peak energy of 1 eV with a FWHM of 18 meV has been achieved on ex-situ annealed samples in N ambient. The temperature dependence of PL peak energy exhibits “S-shaped” behavior in the low temperature regime, indicative of the presence of localized excitons. Raman spectroscopy analysis has been carried out to determine the local structural changes on annealing.

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Microwave-Hydrothermal Synthesis of Transition Metal Tungstates with Nanosized Particles

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.194.209 ◽

2012 ◽

Vol 194 ◽

pp. 209-212 ◽

Cited By ~ 1

Author(s):

Kisla P.F. Siqueira ◽

Anderson Dias

Keyword(s):

Raman Spectroscopy ◽

Structural Changes ◽

Single Phase ◽

Amorphous Matrix ◽

Nanosized Particles ◽

Hydrothermal Processing ◽

X Ray Diffraction ◽

X Ray ◽

Microwave Hydrothermal ◽

Metal Tungstates

Microwave-hydrothermal processing was employed to synthesize Mn and Co tungstates under environmentally friendly conditions. X-ray diffraction showed that crystalline, single-phase materials were produced. Incipient crystallized compounds were also obtained in some conditions, as verified by TEM. For these samples, nanostructured regions could be observed inside the amorphous matrix. Sintered solid-solutions of Mn1-xCoxWO4 compounds were produced to investigate the morphological and structural changes in the resulted ceramic. Raman spectroscopy was used to obtain a reliable set of spectra containing all the Raman-active bands predicted by group-theory calculations.

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In search of low temperature structural changes in Bi2Sr2CaCu2Oy; an X-ray diffraction study

Solid State Communications ◽

10.1016/0038-1098(95)00053-4 ◽

1995 ◽

Vol 94 (4) ◽

pp. 261-265 ◽

Cited By ~ 8

Author(s):

S.T. Johnson ◽

P.D. Hatton ◽

A.J.S. Chowdury ◽

B.M. Wanklyn

Keyword(s):

Low Temperature ◽

Diffraction Study ◽

Structural Changes ◽

X Ray Diffraction ◽

X Ray

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The Effect of Low-Temperature Glow Discharge Nitriding of Duplex Stainless Steel on Absorption and Desorption of Hydrogen

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.183.71 ◽

2011 ◽

Vol 183 ◽

pp. 71-80 ◽

Cited By ~ 2

Author(s):

Bartosz Gołębiowski ◽

Tadeusz Zakroczymski ◽

Wiesław Świątnicki

Keyword(s):

Electron Microscopy ◽

Stainless Steel ◽

Low Temperature ◽

Glow Discharge ◽

Hydrogen Absorption ◽

Nitrided Layer ◽

X Ray Diffraction ◽

X Ray ◽

Scanning Electron ◽

Absorption Of Hydrogen

The effect of the nitrided layers produced on ferritic-austenitic stainless steel to hydrogen absorption and desorption was studied. The layers were formed during low-temperature glow discharge nitriding process. The microstructure of steel after nitriding and cathodic hydrogen charging was investigated by means of X-ray diffraction and by scanning electron microscopy (SEM). One of the objectives was to determine the quantity of hydrogen absorbed by the steel samples with and without the nitrided layer. To determine the quantity of the diffusible and trapped hydrogen, the electrochemical permeation and desorption methods were used. The influence of the nitrided layer on the entry, absorption and desorption of hydrogen was determined. The results revealed that the nitrided layer hinders absorption of hydrogen into and desorption of hydrogen from the membrane.

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Enhancement of the Amorphous to Microcrystalline Phase Transition in Silicon Films Deposited by Sif4-H2-He Plasmas

MRS Proceedings ◽

10.1557/proc-536-493 ◽

1998 ◽

Vol 536 ◽

Cited By ~ 2

Author(s):

G. Cicalai ◽

M. Losurdo ◽

P. Capezzuto ◽

G. Bruno ◽

T. Ligonzo ◽

...

Keyword(s):

Thin Films ◽

Phase Transition ◽

Electrical Properties ◽

Low Temperature ◽

Volume Fraction ◽

Grazing Incidence ◽

X Ray Diffraction ◽

Microcrystalline Silicon ◽

X Ray ◽

Plasma Decomposition

AbstractHydrogenated microcrystalline silicon (μc-Si:H) thin films have been obtained by plasma decomposition of SiF4-H2-He mixtures at low temperature (120 °C). The size of crystalline grain and their volume fraction with respect to the amorphous phase have been found dependent on the r.f. power as evaluated by grazing incidence X-ray diffraction, microRaman and ellipsometry measurements. Chemical and electrical properties change according to the microcrystallinity. Pure and/or highly microcrystalline silicon has been obtained at temperature and r.f. power as low as 120 °C and 15 Watt.

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Low-Temperature X-Ray Diffraction of Frozen Electrolytes

Advances in X-ray Analysis ◽

10.1154/s0376030800001403 ◽

1961 ◽

Vol 5 ◽

pp. 48-56 ◽

Cited By ~ 1

Author(s):

H.J. Weltman

Keyword(s):

Low Temperature ◽

Room Temperature ◽

Structural Changes ◽

Polycrystalline Material ◽

Sample Introduction ◽

X Ray Diffraction ◽

Strip Chart Recorder ◽

X Ray ◽

Chart Recorder ◽

Diffraction Patterns

AbstractA low-temperature X-ray diffraction apparatus has been constructed to study structure and structural changes of electrolytes in the frozen state. This apparatus, which is inexpensive and easy to construct, is an attachment to a standard wide-angle diffractometer. Diffraction patterns may be obtained of various types of materials at any temperature from room temperature to −196°C with a control of ±1°C. The diffraction patterns are recorded on a strip-chart recorder as they are being obtained. Thus, this diffractometer method has several advantages over the camera methods usually employed for low-temperature X-ray diffraction work. A unique sample-introduction method is described which ensures a polycrystalline material suitable for obtaining diffraction patterns. Such patterns are shown for various concentrations of salts in water at several low temperatures, phase transformations being in evidence.

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