scholarly journals A time‐resolved x‐ray absorption study of amorphous Si during pulsed laser irradiation

1986 ◽  
Vol 60 (5) ◽  
pp. 1774-1783 ◽  
Author(s):  
H. C. Gerritsen ◽  
H. van Brug ◽  
F. Bijkerk ◽  
K. Murakami ◽  
M. J. van der Wiel
Keyword(s):  
Laser Irradiation ◽  
Pulsed Laser ◽  
Absorption Study ◽  
Time Resolved ◽  
X Ray ◽  
Amorphous Si ◽  
X Ray Absorption ◽  
Pulsed Laser Irradiation

Time-Resolved X-Ray Absorption of An Amorphous Si Foil During Pulsed Laser Irradiation

1985 ◽  
Vol 51 ◽  
Author(s):  
Kouichi Murakami ◽  
Hans C. Gerritsen ◽  
Hedser Van Brug ◽  
Fred Bijkerk ◽  
Frans W. Saris ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Direct Evidence ◽  
Pulsed Laser ◽  
Time Resolved ◽  
Edge Structure ◽  
X Ray ◽  
Nanosecond Pulsed Laser ◽  
Amorphous Si ◽  
X Ray Absorption ◽  
Pulsed Laser Irradiation

ABSTRACTWe report time-resolved X-ray absorption and extended X-ray absorption fine structure (EXAFS) measurements on amorphous silicon under nanosecond pulsed-laser irradiation. Each measurement was performed with one laser shot in the X-ray energy range from 90 to 300 eV. An X-ray absorption spectrum for induced liquid Si (liq*Si) was first observed above an energy density of 0.17 J/cm2. It differs significantly from the spectrum for amorphous Si and characteristically shows the disappearance of the Si-L(II,III) edge structure at around 100 eV. This phenomenon is interpreted in terms of a significant reduction in the 3s-like character of the unfilled part of the conduction band of liq*Si compared to that of amorphous Si. This is the first direct evidence that liq*Si has a metallic-like electronic structure. Timeresolved EXAFS results are also discussed briefly.

Time-Resolved X-Ray Studies During Pulsed-Laser Irradiation of Ge

1984 ◽  
Vol 35 ◽  
Author(s):  
J.Z. Tischler ◽  
B.C. Larson ◽  
D.M. Mills
Keyword(s):  
Melting Point ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
High Energy ◽  
Measured Temperature ◽  
Time Resolved ◽  
Synchrotron Source ◽  
X Ray ◽  
Pulsed Laser Irradiation

ABSTRACTSynchrotron x-ray pulses from the Cornell High Energy Synchrotron Source (CHESS) have been used to carry out nanosecond resolution measurements of the temperature distrubutions in Ge during UV pulsed-laser irradiation. KrF (249 nm) laser pulses of 25 ns FWHM with an energy density of 0.6 J/cm2 were used. The temperatures were determined from x-ray Bragg profile measurements of thermal expansion induced strain on <111> oriented Ge. The data indicate the presence of a liquid-solid interface near the melting point, and large (1500-4500°C/pm) temperature gradients in the solid; these Ge results are analagous to previous ones for Si. The measured temperature distributions are compared with those obtained from heat flow calculations, and the overheating and undercooling of the interface relative to the equilibrium melting point are discussed.

Nanosecond resolution time-resolved x-ray study of silicon during pulsed-laser irradiation

1986 ◽  
Vol 1 (1) ◽  
pp. 144-154 ◽  
Author(s):  
B. C. Larson ◽  
J. Z. Tischler ◽  
D. M. Mills
Keyword(s):  
Laser Irradiation ◽  
Irradiation Time ◽  
Pulsed Laser ◽  
High Energy ◽  
Resolution Time ◽  
Time Resolved ◽  
Synchrotron Source ◽  
X Ray ◽  
Temperature Distributions ◽  
Pulsed Laser Irradiation

We have used the pulsed time structure of the Cornell High-Energy Synchrotron Source (CHESS) to carry out a nanosecond resolution time-resolved x-ray study of silicon during pulsed-laser irradiation. Time-resolved temperature distributions and interfacial overheating and undercooling were measured on 〈111〉 and 〈100〉 silicon during 25 ns UV laser pulses through the analysis of thermal expansion induced strain. The temperature gradients were found to be > 107 K/cm at the liquid-solid interface and the temperature distributions have been shown to be in agreement with numerical heat flow calculations for these laser conditions. The combined overheating and undercooling (during ∼ 10 m/s melting and ∼ 6 m/s regrowth) was measured to be 110 ± 30 K on 〈111〉 oriented silicon and 50 ± 25 K on 〈100〉 silicon. These values have been interpreted in terms of velocity coefficients of overheating and undercooling.

scholarly journals Overheating In Silicon During Pulsed-Laser Irradiation?

1985 ◽  
Vol 51 ◽  
Author(s):  
B. C. Larson ◽  
J. Z. Tischler ◽  
D. M. Mills
Keyword(s):  
Laser Irradiation ◽  
Thermal Strain ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
High Energy ◽  
Time Resolved ◽  
Synchrotron Source ◽  
Zero Velocity ◽  
The Difference ◽  
Pulsed Laser Irradiation

ABSTRACTNanosecond resolution time-resolved x-ray diffraction measurements of thermal strain have been used to measure the interface temperatures in silicon during pulsed-laser irradiation. The pulsed-time-structure of the Cornell High Energy Synchrotron Source (CHESS) was used to measure the temperature of the liquid-solid interface of <111> silicon during melting with an interface velocity of 11 m/s, at a time of near zero velocity, and at a regrowth velocity of 6 m/s. The results of these measurements indicate 110 K difference between the temperature of the interface during melting and regrowth, and the measurement at zero velocity shows that most of the difference is associated with undercooling during the regrowth phase.

Pulsed Laser Induced Recrystallization of Amorphous Si

2000 ◽  
Vol 638 ◽  
Author(s):  
Sebastiano Tosto
Keyword(s):  
Computer Simulation ◽  
Laser Irradiation ◽  
Rapid Solidification ◽  
3D Model ◽  
Pulsed Laser ◽  
Amorphous Si ◽  
Pulsed Laser Irradiation

AbstractThe paper introduces a 3D model to simulate the recrystallization microstructure of amorphous Si induced by pulsed laser irradiation. The computer simulation shows how the microstructure is modified when introducing into the model the assumption of rapid solidification quenching.

Time‐resolved temperature measurements during pulsed laser irradiation using thin film metal thermometers

1993 ◽  
Vol 64 (9) ◽  
pp. 2615-2623 ◽  
Author(s):  
D. P. Brunco ◽  
J. A. Kittl ◽  
C. E. Otis ◽  
P. M. Goodwin ◽  
Michael O. Thompson ◽  
...  
Keyword(s):  
Thin Film ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Temperature Measurements ◽  
Time Resolved ◽  
Pulsed Laser Irradiation
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