Wavelength-Tunable, Sub-Picosecond Pulsed Laser Diagnostic Tool for III-Nitride Semiconductors

2001 ◽  
Author(s):  
Stephen Teitsworth ◽  
H. C. Casey ◽  
Henry Everitt
Keyword(s):  
Diagnostic Tool ◽  
Pulsed Laser ◽  
Nitride Semiconductors ◽  
Wavelength Tunable ◽  
Laser Diagnostic

Wavelength-Tunable Broadband Frequency-Domain OCT Source Based on Spatially Filtered Sub-10-fs Pulsed Laser

2008 ◽  
Vol 20 (12) ◽  
pp. 994-996
Author(s):  
Tae Joong Eom ◽  
Jae Hee Sung ◽  
Chul-Sik Kee ◽  
Do-Kyeong Ko ◽  
Jongmin Lee ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Pulsed Laser ◽  
Wavelength Tunable ◽  
Broadband Frequency

Laser-Processing for Patterned and Free-Standing Nitride Films

1997 ◽  
Vol 482 ◽  
Author(s):  
M. K. Kelly ◽  
O. Ambacher ◽  
R. Dimitrov ◽  
H. Angerer ◽  
R. Handschuh ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Laser Processing ◽  
Elevated Temperatures ◽  
Pulsed Laser ◽  
Nitride Semiconductors ◽  
Free Standing ◽  
Nitrogen Gas ◽  
Buried Interfaces ◽  
Growth Substrates

AbstractFilms of GaN and related materials can be processed by methods that invoke thermal decomposition, induced by intense illumination with a pulsed laser. At elevated temperatures, the nitride semiconductors undergo decomposition, with the effusion of nitrogen gas. We exploit this mechanism as an alternative to etching for the patterning of nitride films and for the opening of buried interfaces. Films of GaN have been etched to a depth of 1 μm in less than three seconds. This interface decomposition allows in particular the separation of nitride films from transparent growth substrates such as sapphire.

Germanium Extremely Heavily Doped by Ion-Implantation and Laser Annealing: A Photoluminescence Study

1983 ◽  
Vol 23 ◽  
Author(s):  
J. Wagner ◽  
G. Contreras ◽  
A. Compaan ◽  
M. Cardona ◽  
A. Axmann
Keyword(s):  
Ion Implantation ◽  
Diagnostic Tool ◽  
Laser Annealing ◽  
Optical Band Gap ◽  
Pulsed Laser ◽  
Solubility Limit ◽  
Equilibrium Solubility ◽  
Photoluminescence Study ◽  
Pulsed Laser Annealing ◽  
Heavily Doped

ABSTRACTIt has been shown previously that dopant concentrations far above the equilibrium solubility limit can be obtained in semiconductors by pulsed laser annealing of heavily ion implanted material. We exploit this fact to study the photoluminescence of germanium with dopant concentrations up to 1021 cm−3. From this study we obtain information on the filling of higher lying band minima and the shift of the optical band gap as a function of carrier concentration over a much wider range than accessible with bulk doped material. In addition it is shown that photoluminescence provides a diagnostic tool to characterize implanted layers.

Structure and Properties Of III-N Semiconductor Thin Films Grown at Low Temperatures by N-Radical-Assisted Pulsed Laser Deposition

1997 ◽  
Vol 482 ◽  
Author(s):  
F. E. Fernandez ◽  
M. Pumarol ◽  
A. Martinez ◽  
V. Pantojas ◽  
M. Garcia
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Nitride Semiconductors ◽  
Semiconductor Thin Films ◽  
Substrate Temperatures ◽  
Growth Methods ◽  
Gan Film

AbstractThin films of nitride semiconductors are usually grown by means requiring high substrate temperatures. Deposition techniques providing higher kinetic energies of incident species offer an alternative route which might allow growth of good quality films at lower temperatures. Pulsed Laser Deposition can provide higher kinetic energies than most thin film growth methods. However, III-nitride thin films grown by PLD are often nitrogen deficient. We have been able to obtain good stoichiometry for aluminum nitride films even at room temperature by providing atomic nitrogen at low (thermal) energies during growth. Very good orientation can be obtained on (001) sapphire substrates at moderate temperatures (∼ 500 C). AIN films were grown from either AIN or Al targets. We also report on preliminary work by the same method with GaN film growth from a liquid Ga target.

Compact wavelength tunable output around 440 nm pulsed laser for oceanic lidar application

2021 ◽  
Vol 485 ◽  
pp. 126706
Author(s):  
Jiale Zhang ◽  
Jian Ma ◽  
Tingting Lu ◽  
Dong Liu ◽  
Xiaolei Zhu ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Wavelength Tunable

MoTe2-Based Broadband Wavelength Tunable Eye-Safe Pulsed Laser Source at $1.9~\mu$ m

2018 ◽  
Vol 30 (21) ◽  
pp. 1890-1893 ◽  
Author(s):  
Yuzhao Zhang ◽  
Jiawei Wang ◽  
Xiaofeng Guan ◽  
Bin Xu ◽  
Huiying Xu ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Laser Source ◽  
Wavelength Tunable

scholarly journals Mechanism of transient photothermal inactivation of bacteria using a wavelength-tunable nanosecond pulsed laser

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ichiro Tatsuno ◽  
Yuna Niimi ◽  
Makoto Tomita ◽  
Hiroshi Terashima ◽  
Tadao Hasegawa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Optical Absorption ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Wavelength Tunable ◽  
Photothermal Heating ◽  
Pathogenic Viruses ◽  
Site Selective ◽  
Inactivation Of Bacteria ◽  
Pulsed Laser Irradiation

AbstractThere is a great demand for novel disinfection technologies to inactivate various pathogenic viruses and bacteria. In this situation, ultraviolet (UVC) disinfection technologies seem to be promising because biocontaminated air and surfaces are the major media for disease transmission. However, UVC is strongly absorbed by human cells and protein components; therefore, there are concerns about damaging plasma components and causing dermatitis and skin cancer. To avoid these concerns, in this study, we demonstrate that the efficient inactivation of bacteria is achieved by visible pulsed light irradiation. The principle of inactivation is based on transient photothermal heating. First, we provide experimental confirmation that extremely high temperatures above 1000 K can be achieved by pulsed laser irradiation. Evidence of this high temperature is directly confirmed by melting gold nanoparticles (GNPs). Inorganic GNPs are used because of their well-established thermophysical properties. Second, we show inactivation behaviour by pulsed laser irradiation. This inactivation behaviour cannot be explained by a simple optical absorption effect. We experimentally and theoretically clarify this inactivation mechanism based on both optical absorption and scattering effects. We find that scattering and absorption play an important role in inactivation because the input irradiation is inherently scattered by the bacteria; therefore, the dose that bacteria feel is reduced. This scattering effect can be clearly shown by a technique that combines stained Escherichia coli and site selective irradiation obtained by a wavelength tunable pulsed laser. By measuring Live/Dead fluorescence microscopy images, we show that the inactivation attained by the transient photothermal heating is possible to instantaneously and selectively kill microorganisms such as Escherichia coli bacteria. Thus, this method is promising for the site selective inactivation of various pathogenic viruses and bacteria in a safe and simple manner.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

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