Switching of the Optical Properties of Ge2Sb2Te5 Phase Change Material in the Terahertz Frequency Region

Kotaro Makino; Kosaku Kato; Yuta Saito; Paul Fons; Alexander V. Kolobov; Junji Tominaga; Takashi Nakano; Makoto Nakajima

doi:10.1109/IRMMW-THz.2019.8873769

Switching of the Optical Properties of Ge₂Sb₂Te₅ Phase Change Material in the Terahertz Frequency Region

Kotaro Makino, Kosaku Kato, Yuta Saito, Paul Fons, Alexander V. Kolobov, Junji Tominaga, Takashi Nakano, Makoto Nakajima

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Abstract

A reversible insulator-to-metal transition in phase change materials is expected to be usuful for a variety of optoelectronic devices including terahertz (THz) applications. Here, we report on the phase-dependent changes in the optical properties of the thin films of Ge₂Sb₂Te₅ (GST) phase change material. THz time domain spectroscopy measurements were carried out for amorphous and crystalline samples obtained by annealing at different temperatures and the optical properties of the GST films in the THz frequency range were characterized. It was found that the amorphous GST film was almost transparent to THz radiation due to the of absence of free carriers. On the other hand, the crystalline GST films were found to absorb THz radiation depending on the annealing temperature. The index of refraction was found to enhance with increasing annealing temperature. These properties are promising for THz wave devices such as programable amplitude modulator or plasmonic devices.

Original language	English
Title of host publication	IRMMW-THz 2019 - 44th International Conference on Infrared, Millimeter, and Terahertz Waves
Publisher	IEEE Computer Society
ISBN (Electronic)	9781538682852
DOIs	https://doi.org/10.1109/IRMMW-THz.2019.8873769
Publication status	Published - 2019 Sept
Externally published	Yes
Event	44th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2019 - Paris, France Duration: 2019 Sept 1 → 2019 Sept 6

Publication series

Name	International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz
Volume	2019-September
ISSN (Print)	2162-2027
ISSN (Electronic)	2162-2035

Conference

Conference	44th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2019
Country/Territory	France
City	Paris
Period	19/9/1 → 19/9/6

ASJC Scopus subject areas

Energy Engineering and Power Technology
Electrical and Electronic Engineering

Access to Document

10.1109/IRMMW-THz.2019.8873769

Cite this

Makino, K., Kato, K., Saito, Y., Fons, P., Kolobov, A. V., Tominaga, J., Nakano, T., & Nakajima, M. (2019). Switching of the Optical Properties of Ge₂Sb₂Te₅ Phase Change Material in the Terahertz Frequency Region. In IRMMW-THz 2019 - 44th International Conference on Infrared, Millimeter, and Terahertz Waves [8873769] (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz; Vol. 2019-September). IEEE Computer Society. https://doi.org/10.1109/IRMMW-THz.2019.8873769

Switching of the Optical Properties of Ge₂Sb₂Te₅ Phase Change Material in the Terahertz Frequency Region. / Makino, Kotaro; Kato, Kosaku; Saito, Yuta et al.

IRMMW-THz 2019 - 44th International Conference on Infrared, Millimeter, and Terahertz Waves. IEEE Computer Society, 2019. 8873769 (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz; Vol. 2019-September).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Makino, K, Kato, K, Saito, Y, Fons, P, Kolobov, AV, Tominaga, J, Nakano, T & Nakajima, M 2019, Switching of the Optical Properties of Ge₂Sb₂Te₅ Phase Change Material in the Terahertz Frequency Region. in IRMMW-THz 2019 - 44th International Conference on Infrared, Millimeter, and Terahertz Waves., 8873769, International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, vol. 2019-September, IEEE Computer Society, 44th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2019, Paris, France, 19/9/1. https://doi.org/10.1109/IRMMW-THz.2019.8873769

Makino K, Kato K, Saito Y, Fons P, Kolobov AV, Tominaga J et al. Switching of the Optical Properties of Ge₂Sb₂Te₅ Phase Change Material in the Terahertz Frequency Region. In IRMMW-THz 2019 - 44th International Conference on Infrared, Millimeter, and Terahertz Waves. IEEE Computer Society. 2019. 8873769. (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz). doi: 10.1109/IRMMW-THz.2019.8873769

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abstract = "A reversible insulator-to-metal transition in phase change materials is expected to be usuful for a variety of optoelectronic devices including terahertz (THz) applications. Here, we report on the phase-dependent changes in the optical properties of the thin films of Ge2Sb2Te5 (GST) phase change material. THz time domain spectroscopy measurements were carried out for amorphous and crystalline samples obtained by annealing at different temperatures and the optical properties of the GST films in the THz frequency range were characterized. It was found that the amorphous GST film was almost transparent to THz radiation due to the of absence of free carriers. On the other hand, the crystalline GST films were found to absorb THz radiation depending on the annealing temperature. The index of refraction was found to enhance with increasing annealing temperature. These properties are promising for THz wave devices such as programable amplitude modulator or plasmonic devices.",

author = "Kotaro Makino and Kosaku Kato and Yuta Saito and Paul Fons and Kolobov, {Alexander V.} and Junji Tominaga and Takashi Nakano and Makoto Nakajima",

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AU - Kolobov, Alexander V.

AU - Tominaga, Junji

AU - Nakano, Takashi

AU - Nakajima, Makoto

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