Nanocrystalline Ge Synthesis by Picosecond Pulsed Laser Induced Melting and Rapid Soldddtcation

1996 ◽  
Vol 452 ◽  
Author(s):  
J. Solis ◽  
J. Siegel ◽  
C. Garcia ◽  
J. Jimenez ◽  
R. Serna
Keyword(s):  
Crystallite Size ◽  
Amorphous Matrix ◽  
Pulsed Laser ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Correlation Lengths ◽  
Glass Substrates ◽  
Solidification Kinetics ◽  
Rapidly Solidified ◽  
Nm Range

AbstractMelting and rapid solidification has been induced in DC-sputtered amorphous Ge (a-Ge) films on glass substrates by irradiation with picosecond laser pulses at 583 nm. The melting-solidification kinetics has been followed by means of real time reflectivity measurements with ns resolution and the structure of the rapidly solidified material has been analyzed by means of Raman spectroscopy in micro-Raman configuration. The results obtained show that for laser pulse fluences above a certain threshold recalescence occurs during solidification leading to the formation of nanocrystalline Ge embedded in an amorphous matrix. The phonon correlation length (L) obtained from the Raman spectra of the irradiated regions has been used to analyze the evolution of the crystallite size with the laser fluence. For low fluences above the recalescence threshold, the values of L are in the 8–10 nm range. However, if the fluence is sufficiently increased, the crystallite size shows a clear linear dependence on the fluence with phonon correlation lengths scaling from 6 to 13 nm.

Raman Spectroscopy Study of Pulsed Laser Induced Structural Transformations in Amorphous Ge Films

1995 ◽  
Vol 397 ◽  
Author(s):  
C. García ◽  
A.C. Prieto ◽  
J. Jiménez ◽  
J. Siegel ◽  
J. Solís ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Crystallization Process ◽  
Bond Angle ◽  
Pulsed Laser ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Structural Transformations ◽  
Spectroscopy Study ◽  
Glass Substrates ◽  
Average Bond

ABSTRACTStructural transformations induced in amorphous Ge films by picosecond laser pulses are studied by means of Raman spectroscopy and their dependence on parameters like the pulse fluence or the thermal conductivity of the substrate are analyzed. A correlation length model is used for studying the crystallization process, while the average bond angle distortion is used for determining the state of relaxation of the amorphous phase. Silicon and glass substrates are compared.

Growth and Characterization of Urea Doped p-Type ZnO Thin Film Grown by Pulsed Laser Deposition

2009 ◽  
Vol 67 ◽  
pp. 127-130 ◽  
Author(s):  
Majumdar Sayanee ◽  
Banerji Pallab
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Laser Deposition ◽  
Zno Films ◽  
Group V ◽  
Xrd Pattern ◽  
Glass Substrates ◽  
P Type

In the present study we have used urea as the source for doping nitrogen in ZnO since the most successful acceptor type dopant is the group V element like nitrogen. The nitrogen doped ZnO films have been deposited on glass substrates using Pulsed Laser Deposition technique using 248 nm KrF laser at energy 300 mJ by varying the number of laser pulses with a repetition rate of 10 pulse/sec in vacuum (10-6 mbar) at a constant temperature of 300 °C. The XRD pattern confirms the formation of wurtzite structure of ZnO, which is polycrystalline in nature. We have also performed UV absorption spectroscopy and the band gap is found to be 3.4 eV. Resistivity of the film increases with the increase of thickness for the undoped ZnO samples where the carrier concentrations are found to be of the order of 1017 cm-3. The mobility of the as-grown film is found to be 24.9 cm2/V-s. After doping with nitrogen the carrier concentration drops to the order of 1015 cm-3 and the mobility becomes 1.5 cm2/V-s. The mobility slightly varies with thickness. The resistivity increases to 1.3 KΩ-cm and the film shows p-type behavior. The results are explained on the basis of the available theory.

Low Temperature Crystallization of PbTiO3 Thin Film by Excimer Laser Irradiation

1999 ◽  
Vol 596 ◽  
Author(s):  
T. Mihara ◽  
S Mochizuki ◽  
T. Ishida ◽  
Y Sato ◽  
J. Nishii
Keyword(s):  
Perovskite Structure ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Structure Morphology ◽  
Excimer Laser Irradiation ◽  
Low Temperature Crystallization ◽  
Temperature Crystallization

AbstractLowering the fabrication temperature for ferroelectric films is very important not only for silicon monolithic circuits but also for various substrates. Amorphous PbTiO3 thin films were prepared on glass substrates using ArF pulsed laser deposition (PLD). They were subsequently treated by a laser-induced phase transformation technique to achieve a perovskite structure. After irradiation by an ArF pulsed laser with an energy density 50mJ/cm2 in air, the films crystallized into the perovskite structure. It was possible to maintain the substrate at room temperature during the whole fabrication process. The structure, morphology and composition of the films were characterized by X-ray diffraction diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), respectively. The surface of film irradiated with a laser was often rather rough and peeled off everywhere. It was necessary to control the number of laser pulses to avoid damaging the films. The effects of chemical composition and fabrication temperature are also discussed.

scholarly journals Study of Structure and Properties of Fe-Based Amorphous Ribbons after Pulsed Laser Interference Heating

2020 ◽  
Vol 29 (10) ◽  
pp. 6277-6285
Author(s):  
Olaf Czyż ◽  
Jan Kusiński ◽  
Agnieszka Radziszewska ◽  
Zhongquan Liao ◽  
Ehrenfried Zschech ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Laser Heating ◽  
Amorphous Matrix ◽  
Dendritic Structure ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Structure And Properties ◽  
Soft Magnetic ◽  
Tem Analysis ◽  
Amorphous Ribbons

AbstractThe paper is devoted to the study of microstructural and magnetic properties of the Fe-based amorphous ribbons after interference pulsed laser heating. The ternary amorphous alloy FeSiB, as well as the multi-component alloys FeCuSiB and FeCuNbSiB, was subjected to laser pulses to induce crystallization in many microislands simultaneously. Structure and properties changes occurred in laser-heated dots. Detailed TEM analysis from a single dot shows the presence of FeSi(α) nanocrystals in the amorphous matrix. The FeSiB alloy is characterized after conventional crystallization by a dendritic structure; however, the alloys with copper as well copper and niobium additions are characterized by the formation of equiaxed crystals in the amorphous matrix. Amorphous alloys before and after the laser heating are soft magnetic; however, conventional crystallization leads to a deterioration of the soft magnetic properties of the material.

Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

2009 ◽  
Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Photon ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Laser Stimulation ◽  
Two Photon ◽  
Resolution Improvement ◽  
Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

Electric field probing by picosecond laser pulses

1992 ◽  
Vol 28 (12) ◽  
pp. 1137 ◽  
Author(s):  
A. Krotkus ◽  
V. Pašiškevičius
Keyword(s):  
Electric Field ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Picosecond Laser Pulses

scholarly journals Effects of Accumulated Energy on Nanoparticle Formation in Pulsed-Laser Dewetting of AgCu Thin Films

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
H. K. Lin ◽  
C. W. Huang ◽  
Y. H. Lin ◽  
W. S. Chuang ◽  
J. C. Huang
Keyword(s):  
Pulsed Laser ◽  
Blue Shift ◽  
High Energy ◽  
Low Energy ◽  
Nanoparticle Formation ◽  
Energy Accumulation ◽  
Glass Substrates ◽  
Peak Absorption ◽  
Two Peaks ◽  
Sputtering System

AbstractAg50Cu50 films were deposited on glass substrates by a sputtering system. Effects of accumulated energy on nanoparticle formation in pulse-laser dewetting of AgCu films were investigated. The results showed that the properties of the dewetted films were found to be dependent on the magnitude of the energy accumulated in the film. For a low energy accumulation, the two distinct nanoparticles had rice-shaped/Ag60Cu40 and hemispherical/Ag80Cu20. Moreover, the absorption spectra contained two peaks at 700 nm and 500 nm, respectively. By contrast, for a high energy accumulation, the nanoparticles had a consistent composition of Ag60Cu40, a mean diameter of 100 nm and a peak absorption wavelength of 550 nm. Overall, the results suggest that a higher Ag content of the induced nanoparticles causes a blue shift of the absorption spectrum, while a smaller particle size induces a red shift.

scholarly journals Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse

1982 ◽  
Vol 1 (1) ◽  
pp. 37-43 ◽  
Author(s):  
V. S. Antonov ◽  
V. S. Letokhov ◽  
Yu. A. Matveyets ◽  
A. N. Shibanov
Keyword(s):  
Laser Radiation ◽  
Kinetic Energy ◽  
Crystal Surface ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Molecular Ions ◽  
Laser Radiation Intensity ◽  
Ion Sputtering ◽  
Absorbed Energy ◽  
Picosecond Laser Pulse

This paper presents the results of observation of sputtering of neutral molecules and ions from the crystal adenine surface induced by fourth-harmonic Nd:YAG laser radiation with a pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4 J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The experiment shows that the threshold of adenine molecular ion sputtering is connected with absorbed energy density in upper layers of the crystal surface but not by laser radiation intensity.

Sign in / Sign up

Export Citation Format

Share Document