Bilayer Structures Obtained by Pulsed Laser Quenching of Binary Systems

1988 ◽  
Vol 100 ◽  
Author(s):  
P. Baeri ◽  
G. Foti ◽  
M. G. Grimaldi ◽  
F. Priolo ◽  
R. Reitano ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Binary Systems ◽  
Pulsed Laser ◽  
Epitaxial Layers ◽  
Silicon Substrates ◽  
High Fluence ◽  
Laser Quenching ◽  
Ion Implanted

ABSTRACTNiSi and Ni2Si layers on silicon substrates as well as high fluence Si(As) ion implanted layers,have been rapidly melted by 30 ns Nd laser pulse irradiation.The energy density ranged between 0.4 and 1.2 J/cm2. Bilayer structures have been observed when the energy density has been chosen properly.Buried epitaxial layers together with an amorphous or a policrystalline layer on top,have been detected by RBS and TEM measurements.

Pulsed Laser Melting of Graphite

1985 ◽  
Vol 51 ◽  
Author(s):  
G. Braunstein ◽  
J. Steinbeck ◽  
M. S. Dresselhaus ◽  
G. Dresselhaus ◽  
B. S. Elman ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Crystalline Structure ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Pulsed Laser ◽  
Laser Melting ◽  
Liquid Carbon ◽  
Pulse Energy Density ◽  
Ion Implanted

ABSTRACTExperimental evidence for laser melting of graphite, by irradiation with 30ns pulses from a ruby laser, is presented. RBS-channeling analysis, Raman scattering and TEM measurements reveal that the surface of graphite melts at a threshold energy density of about 0.6 J/cm2. For laser pulse energy densities above 0.6 J/cm2, the melt front penetration depth increases nearly linearly with increasing energy density. An intense emission of carbon particles during and after irradiation is observed. The thickness of the carbon layer removed in this process also increases nearly linearly with increasing pulse fluence. A dramatic redistribution of ion implanted impurities is also observed. Furthermore, the crystalline structure of the resolidified material is shown to depend on the energy density of the laser pulse. In order to explain these phenomena, a model for laser melting of graphite at high temperatures to form liquid carbon has been developed in which a free electron gas approximation is used to describe the properties of liquid carbon. The model is solved numerically to give the time and depth dependences of the temperature as a function of the laser pulse energy density. Very good agreement is found between the observed melt depth dependence on laser pulse energy density, as determined by RBS-channeling, and the model calculations. The redistribution of ion implanted impurities and the modification of the crystalline structure, caused by the pulsed laser irradiation, are also consistent with the model and permit the determination, for the first time, of interfacial segregation coefficients for impurities in liquid carbon. The model also predicts that liquid carbon at low pressure (p < 1 kbar) has metallic properties.

The effects of the atmosphere on the surface modification of alumina by pulsed-laser-irradiation

1997 ◽  
Vol 12 (7) ◽  
pp. 1747-1754 ◽  
Author(s):  
Siqi Cao ◽  
A. J. Pedraza ◽  
L. F. Allard ◽  
D. H. Lowndes
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Thin Layer ◽  
Amorphous Phase ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Near Surface ◽  
Metallic Particles ◽  
Cellular Microstructure

A near-surface thin layer is melted when alumina is pulsed-laser-irradiated in an Ar–4% H2 atmosphere or in air. A thin layer of amorphous phase forms when the substrates are irradiated in Ar–4% H2 at 1 to 1.3 J/cm2 with multiple laser pulses. Amorphous phase is also found in samples laser-irradiated in air and oxygen. After a laser pulse at an energy density of 1.6 J/cm2 or higher the melt solidifies epitaxially from the unmelted substrate with a cellular microstructure. There is a decrease in the cooling rate of the melt as the laser energy density is increased because more heat must be dissipated. The amorphous phase forms when the heat input due to the laser pulse produces a superheated melt that cools down sufficiently fast to avoid crystallization. Very small particles of aluminum in the laser-melted and subsequently solidified layer are observed only in samples laser-irradiated in an Ar–4% H2 atmosphere. In this reducing atmosphere, the alumina is possibly reduced to metallic aluminum which is mixed into the melt by the turbulence provoked by the laser pulses. The effects of these metallic particles on copper deposition when the irradiated substrates are immersed in an electroless bath are discussed.

Metallic Glasses and Metastable Crystalline Phases Produced by Picosecond Pulsed Laser Quenching

1983 ◽  
Vol 28 ◽  
Author(s):  
C.-J. Lin ◽  
F. Spaepen
Keyword(s):  
Laser Irradiation ◽  
Metallic Glasses ◽  
Glass Formation ◽  
Binary Systems ◽  
Pulsed Laser ◽  
Crystalline Phases ◽  
Laser Quenching ◽  
Ultrafast Cooling ◽  
Formation Range ◽  
Pulsed Laser Irradiation

ABSTRACTThe mechanism of ultrafast cooling (1012K sec−1) by picosecond pulsed laser irradiation is reviewed, and it is demonstrated that only partitionless transformations can occur. The glass formation range in a number of binary systems is reviewed, demonstrating that many glasses can be formed below the To-line. The formation of metastable crystalline alloys in the Fe-B, Ni-Nb, Cu-Co and Au-Co systems is reported.

Dynamic behaviors of pulsed-laser annealing in ion-implanted silicon studied by measuring the optical reflectance

1979 ◽  
Author(s):  
Kouichi Murakami ◽  
Kenji Gamo ◽  
Susumu Namba ◽  
Mitsuo Kawabe ◽  
Yoshinobu Aoyagi ◽  
...  
Keyword(s):  
Laser Annealing ◽  
Pulsed Laser ◽  
Optical Reflectance ◽  
Dynamic Behaviors ◽  
Pulsed Laser Annealing ◽  
Ion Implanted

Effect of pulsed laser target cleaning on ionisation and acceleration of ions in a plasma produced by a femtosecond laser pulse

2005 ◽  
Vol 35 (10) ◽  
pp. 953-958 ◽  
Author(s):  
Roman V Volkov ◽  
A A Vorobiev ◽  
Vyacheslav M Gordienko ◽  
M S Dzhidzhoev ◽  
I M Lachko ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Femtosecond Laser Pulse ◽  
Pulsed Laser ◽  
Laser Target

Low-energy femtosecond pulsed laser deposition of cerium (IV) oxide thin films on silicon substrates

2021 ◽  
pp. 126323
Author(s):  
Joseph A. De Mesa ◽  
Angelo P. Rillera ◽  
Melvin John F. Empizo ◽  
Nobuhiko Sarukura ◽  
Roland V. Sarmago ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Low Energy ◽  
Laser Deposition ◽  
Silicon Substrates ◽  
Oxide Thin Films ◽  
Femtosecond Pulsed Laser

Large-sized-mismatched group-V element doped ZnO films fabricated on silicon substrates by pulsed laser deposition

Vacuum ◽  
2010 ◽  
Vol 84 (11) ◽  
pp. 1306-1309 ◽  
Author(s):  
Xiaofeng Xu ◽  
Yiqun Shen ◽  
Ning Xu ◽  
Wei Hu ◽  
Jushui Lai ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Zno Films ◽  
Silicon Substrates ◽  
Group V ◽  
Doped Zno
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