Ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using single-shot imaging spectroscopy

Journal Article · Mon Jun 30 04:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4886969· OSTI ID:22304463

Takeda, Jun; Oba, Wataru; Minami, Yasuo; Katayama, Ikufumi ^[1]; Saiki, Toshiharu ^[2]

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1. Department of Physics, Graduate School of Engineering, Yokohama National University, Yokohama 240-8501 (Japan)
2. Graduate School of Science and Technology, Keio University, Yokohama 223-8522 (Japan)

We have observed an irreversible ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using broadband single-shot imaging spectroscopy. The absorbance change that accompanied the ultrafast amorphization was measured via single-shot detection even for laser fluences above the critical value, where a permanent amorphized mark was formed. The observed rise time to reach the amorphization was found to be ∼130–200 fs, which was in good agreement with the half period of the A{sub 1} phonon frequency in the octahedral GeTe{sub 6} structure. This result strongly suggests that the ultrafast amorphization can be attributed to the rearrangement of Ge atoms from an octahedral structure to a tetrahedral structure. Finally, based on the dependence of the absorbance change on the laser fluence, the stability of the photoinduced amorphous phase is discussed.

• OSTI ID: 22304463
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 26 Vol. 104; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMORPHOUS STATE
ANTIMONY COMPOUNDS
ATOMS
CHALCOGENIDES
CRYSTAL STRUCTURE
DETECTION
GERMANIUM COMPOUNDS
LASER RADIATION
PHONONS
PULSE RISE TIME
SPECTROSCOPY
STABILITY
TELLURIUM COMPOUNDS
TERNARY ALLOY SYSTEMS
THIN FILMS