Stimulated crystallization of melt-quenched Ge{sub 2}Sb{sub 2}Te{sub 5} films employing femtosecond laser double pulses

Journal Article · Sat Dec 15 04:00:00 EST 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4770493· OSTI ID:22089654

Cotton, Rebecca L.; Siegel, Jan ^[1]

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1. Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, E-28006 Madrid (Spain)

The phase transformation of Ge{sub 2}Sb{sub 2}Te{sub 5} films from the melt-quenched amorphous phase into the crystalline phase induced by 800 nm, 100 fs laser pulses has been studied. For partly amorphized films, progressive crystallization could be induced by single pulses, which can be explained by growth of already existing crystalline embryos. For completely amorphized films, it was not possible to induce crystallization with one or two consecutive pulses; three pulses being the threshold for the onset of crystallization. By employing a fs laser double pulse with an adjustable inter-pulse delay, partial crystallization could be triggered for a delay range of 200 fs-100 ps, while for longer delays no crystallization was possible. The time window for stimulated crystallization can be related to the relaxation dynamics of free electrons excited by the first pulse, which are further excited by the second pulse still remaining in the excited state. Our results indicate that the lifetime of excited electrons in melt-quenched amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} is Almost-Equal-To 100 ps.

• OSTI ID: 22089654
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 112; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMORPHOUS STATE
ANTIMONY COMPOUNDS
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTALLIZATION
ENERGY BEAM DEPOSITION
EXCITED STATES
GERMANIUM COMPOUNDS
GLASS
LASER RADIATION
LIFETIME
PULSED IRRADIATION
RELAXATION
SEMICONDUCTOR MATERIALS
TERBIUM COMPOUNDS
THIN FILMS