Influence of pulse duration on the amorphization of GeSb thin films under ultrashort laser pulses

Wiggins, S. M.; Solı́s, J.; Afonso, Carmen N.

doi:10.1063/1.1759062

Cited by 16 publications

(15 citation statements)

References 24 publications

(18 reference statements)

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“…5 Over past decades, binary alloys such as GeTe and Sb 2 Te 3 and ternary alloys, located along the GeTe-Sb 2 Te 3 pseudobinary line, were intensively studied both theoretically 6 and experimentally in relation to their applications in optical phase-change data storage. These studies explored a vast number of parameters including pulse duration, 7 wavelength, 8 pulse energies, 9 the role of oxygen impurities, 10 vacancies, 11 and local structure. 12 Time-resolved optical studies using ps and fs laser pulses have already revealed important details of the phase transition, such as the existence of three distinct stages, namely, rapid melting, solidification, and slow relaxation.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of laser-induced phase switching in GeTe films

Gawełda

Siegel

Afonso

et al. 2011

Journal of Applied Physics

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High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture APL: Org. Electron. Photonics 5, 238 (2012) High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture Appl. Phys. Lett. 101, 173304 (2012) Response to "Comment on 'Silver/silicon dioxide/silver sandwich films in the blue-to-red spectral regime with negative-real refractive index'" [Appl. Phys. Lett. 101, 156101 (2012)] Appl. Phys. Lett. 101, 156102 (2012) On the determination of the glass forming ability of AlxZr1−x alloys using molecular dynamics, Monte Carlo simulations, and classical thermodynamics J. Appl. Phys. 112, 073508 (2012) Enhanced photoanode properties of epitaxial Ti doped α-Fe2O3 (0001) thin films Appl. Phys. Lett. 101, 133908 (2012) Additional information on J. Appl. Phys. Phase switching in GeTe thin films (grown using a modified metal organic chemical vapor deposition system) upon pulsed femtosecond and nanosecond laser irradiation has been studied. Two in situ methods, i.e., optical microscopy and real-time reflectivity measurements, have been used in order to compare the optical response before and after phase change and to follow the phase change dynamics with a time resolution close to 400 ps. The results show that cycling is possible under irradiation with both fs and ns pulses using single pulses for amorphization and multiple pulses for crystallization. The use of ns pulses favors the crystalline-to-amorphous phase transformation, with a characteristic transformation time of $15 ns. The presence of the liquid phase was identified and temporally resolved, featuring a well-defined transient reflectivity state, in between those of the crystalline and amorphous phases. We have also studied the role of material configuration in the phase change dynamics and the mechanisms involved in the re-crystallization process.

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Section: Introductionmentioning

confidence: 99%

Dynamics of laser-induced phase switching in GeTe films

Gawełda

Siegel

Afonso

et al. 2011

Journal of Applied Physics

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“…However, the pulse duration of the femtosecond laser is much shorter than the thermal diffusion time, which results in incomplete re-distribution of the absorbed laser energy in both the horizontal and vertical directions. The ultra-short pulse duration deposits the energy to heat up the sample in less than one hundred femtoseconds (10 À13 s) with a rapid cooling rate (Wiggins et al 2004). Such a steep temperature gradient makes it difficult for heat to dissipate to the surrounding area and thus confines the heat inside a much smaller area of the phase change film to produce these nano-sized features.…”

Section: Methodsmentioning

confidence: 99%

Laser Nano-Patterning for Large Area Nanostructure Fabrication

Tan

Hong

2008

International Journal of Optomechatronics

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The laser nano-patterning technique described here makes use of laser irradiation through a transparent microlens array to generate nano-patterns over a large area in a short time. A femtosecond laser and an excimer laser were used to pattern phase change and photoresist thin films. Due to the ultra-short pulse duration of the femtosecond laser (800 nm/100 fs) and multi-photon absorption effect, nano-patterns down to about 50 nm in feature size were created in the phase change films by laser irradiation at an optimized laser power. By using a 248 nm/23 ns KrF excimer laser, feature sizes of approximately 80 nm can be obtained on a photoresist surface, which implies a high resolution of one third of the laser wavelength. Such small feature size shows that it is possible for the laser nano-patterning technique to overcome the optical diffraction limit for large area surface nano-structuring.

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“…This research has largely concentrated on Sbrich films. [7][8][9][10][11][12] It was shown that cycling between the crystalline and amorphous phases of 25-nm-thick GeSb films induced by single laser pulses of duration of 100 fs or 20 ps is achieved in the 400-800 nm wavelength range. 11 The phase transformation dynamics of GeSb materials upon picosecond and femtosecond laser-pulse excitations was investigated.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10][11][12] It was shown that cycling between the crystalline and amorphous phases of 25-nm-thick GeSb films induced by single laser pulses of duration of 100 fs or 20 ps is achieved in the 400-800 nm wavelength range. 11 The phase transformation dynamics of GeSb materials upon picosecond and femtosecond laser-pulse excitations was investigated. [10][11] The shortest transformation times have been reported and induced by 30 ps pulses at 583 nm in 25-nmthick Sb-rich GeSb films on glass substrates where the complete a ↔ c crystallization transformation times were as low as ∼ 400 ps.…”

Section: Introductionmentioning

confidence: 99%

“…11 The phase transformation dynamics of GeSb materials upon picosecond and femtosecond laser-pulse excitations was investigated. [10][11] The shortest transformation times have been reported and induced by 30 ps pulses at 583 nm in 25-nmthick Sb-rich GeSb films on glass substrates where the complete a ↔ c crystallization transformation times were as low as ∼ 400 ps. 8 In the case of the GeSbTe system, reversible and stable phase transformations have been demonstrated in Ge 2 Sb 2 Te 5 films upon irradiation with single laser pulses as short as 30 ps, 12 and for femtosecond pulses, only amorphization transformation has been achieved in Ge 2 Sb 2 Te 5 films with single 120 fs laser pulses.…”

Section: Introductionmentioning

confidence: 99%

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DYNAMICS OF AMORPHIZATION INDUCED IN CRYSTALLINE Ge₁Sb₂Te₄ FILMS BY SINGLE FEMTOSECOND PULSES

Yao

Jin

et al. 2007

Surf. Rev. Lett.

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The dynamics and the conditions of amorphous transitions induced in a Ge 1 Sb 2 Te 4 system upon a single femtosecond (fs) pulse melting were studied by real-time reflectivity measurements. The system has a multilayer structure of 100 nm ZnS-SiO 2 /(15-100 nm) Ge 1 Sb 2 Te 4 /120 nm ZnS-SiO 2 /0.6 mm polycarbonate substrate. It is shown that under optimum conditions amorphization is completed within 900 ps. The thickness of the phase change layer plays an important role in controlling the heat flow conditions in the system upon a fs pulse irradiation. The use of the fs laser pulse leads to a situation in which the pulse energy is deposited within a very short time in a thin surface layer, leading to heating or melting. The so-generated steep temperature gradient is subsequently smoothed by heat diffusion toward the substrate. The relative thermal process and effects are estimated. The calculated results are consisted with those from real-time reflectivity measurements. The mechanism of crystalline to amorphous transition triggered by single fs laser pulses is discussed.

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Influence of pulse duration on the amorphization of GeSb thin films under ultrashort laser pulses

Cited by 16 publications

References 24 publications

Dynamics of laser-induced phase switching in GeTe films

Dynamics of laser-induced phase switching in GeTe films

Laser Nano-Patterning for Large Area Nanostructure Fabrication

DYNAMICS OF AMORPHIZATION INDUCED IN CRYSTALLINE Ge₁Sb₂Te₄ FILMS BY SINGLE FEMTOSECOND PULSES

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Influence of pulse duration on the amorphization of GeSb thin films under ultrashort laser pulses

Cited by 16 publications

References 24 publications

Dynamics of laser-induced phase switching in GeTe films

Dynamics of laser-induced phase switching in GeTe films

Laser Nano-Patterning for Large Area Nanostructure Fabrication

DYNAMICS OF AMORPHIZATION INDUCED IN CRYSTALLINE Ge1Sb2Te4 FILMS BY SINGLE FEMTOSECOND PULSES

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DYNAMICS OF AMORPHIZATION INDUCED IN CRYSTALLINE Ge₁Sb₂Te₄ FILMS BY SINGLE FEMTOSECOND PULSES