Anisotropic Terahertz Emission from Bi2Se3 Thin Films with Inclined Crystal Planes

Sun Young Hamh; Soon Hee Park; Jeongwoo Han; Jeong Heum Jeon; Se Jong Kahng; Sung Kim; Suk Ho Choi; Namrata Bansal; Seongshik Oh; Joonbum Park; Jun Sung Kim; Jae Myung Kim; Do Young Noh; Jong Seok Lee

doi:10.1186/s11671-015-1190-y

Anisotropic Terahertz Emission from Bi₂Se₃ Thin Films with Inclined Crystal Planes

Sun Young Hamh, Soon Hee Park, Jeongwoo Han, Jeong Heum Jeon, Se Jong Kahng, Sung Kim, Suk Ho Choi, Namrata Bansal, Seongshik Oh, Joonbum Park, Jun Sung Kim, Jae Myung Kim, Do Young Noh, Jong Seok Lee

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

Abstract

We investigate the surface states of topological insulator (TI) Bi₂Se₃ thin films grown on Si nanocrystals and Al₂O₃ substrates by using terahertz (THz) emission spectroscopy. Compared to bulk crystalline Bi₂Te₂Se, film TIs exhibit distinct behaviors in the phase and amplitude of emitted THz radiation. In particular, Bi₂Se₃ grown on Al₂O₃ shows an anisotropic response with a strong modulation of the THz signal in its phase. From x-ray diffraction, we find that the crystal plane of the Bi₂Se₃ films is inclined with respect to the plane of the Al₂O₃ substrate by about 0.27°. This structural anisotropy affects the dynamics of photocarriers and hence leads to the observed anisotropic response in the THz emission. Such relevance demonstrates that THz emission spectroscopy can be a sensitive tool to investigate the fine details of the surface crystallography and electrostatics of thin film TIs.

Original language	English
Article number	489
Pages (from-to)	1-6
Number of pages	6
Journal	Nanoscale Research Letters
Volume	10
Issue number	1
DOIs	https://doi.org/10.1186/s11671-015-1190-y
Publication status	Published - 2015 Dec 1

Bibliographical note

Funding Information:
This work was supported in part by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (nos. 2012R1A1A1013290, 2008-0061906, 2015R1A1A05001560, 2015R1A5A1009962, and 2008-0062257) and also by the Top Brand Project through a grant provided by the Gwangju Institute of Science and Technology in 2014. Work at Rutgers was supported by the Office of Naval Research (N000141210456). The work at POSTECH was supported by the NRF through the SRC Program (no. 2011-0030785).

Publisher Copyright:
© 2015, Hamh et al.

Keywords

BiSe
Terahertz emission
Thin film
Topological insulator

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics

Access to Document

10.1186/s11671-015-1190-y

Cite this

@article{f1d16924b73a4297bb4fe4a4a449c1a9,

title = "Anisotropic Terahertz Emission from Bi2Se3 Thin Films with Inclined Crystal Planes",

abstract = "We investigate the surface states of topological insulator (TI) Bi2Se3 thin films grown on Si nanocrystals and Al2O3 substrates by using terahertz (THz) emission spectroscopy. Compared to bulk crystalline Bi2Te2Se, film TIs exhibit distinct behaviors in the phase and amplitude of emitted THz radiation. In particular, Bi2Se3 grown on Al2O3 shows an anisotropic response with a strong modulation of the THz signal in its phase. From x-ray diffraction, we find that the crystal plane of the Bi2Se3 films is inclined with respect to the plane of the Al2O3 substrate by about 0.27°. This structural anisotropy affects the dynamics of photocarriers and hence leads to the observed anisotropic response in the THz emission. Such relevance demonstrates that THz emission spectroscopy can be a sensitive tool to investigate the fine details of the surface crystallography and electrostatics of thin film TIs.",

keywords = "BiSe, Terahertz emission, Thin film, Topological insulator",

author = "Hamh, {Sun Young} and Park, {Soon Hee} and Jeongwoo Han and Jeon, {Jeong Heum} and Kahng, {Se Jong} and Sung Kim and Choi, {Suk Ho} and Namrata Bansal and Seongshik Oh and Joonbum Park and Kim, {Jun Sung} and Kim, {Jae Myung} and Noh, {Do Young} and Lee, {Jong Seok}",

note = "Funding Information: This work was supported in part by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (nos. 2012R1A1A1013290, 2008-0061906, 2015R1A1A05001560, 2015R1A5A1009962, and 2008-0062257) and also by the Top Brand Project through a grant provided by the Gwangju Institute of Science and Technology in 2014. Work at Rutgers was supported by the Office of Naval Research (N000141210456). The work at POSTECH was supported by the NRF through the SRC Program (no. 2011-0030785). Publisher Copyright: {\textcopyright} 2015, Hamh et al.",

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T1 - Anisotropic Terahertz Emission from Bi2Se3 Thin Films with Inclined Crystal Planes

AU - Hamh, Sun Young

AU - Park, Soon Hee

AU - Han, Jeongwoo

AU - Jeon, Jeong Heum

AU - Kahng, Se Jong

AU - Kim, Sung

AU - Choi, Suk Ho

AU - Bansal, Namrata

AU - Oh, Seongshik

AU - Park, Joonbum

AU - Kim, Jun Sung

AU - Kim, Jae Myung

AU - Noh, Do Young

AU - Lee, Jong Seok

N1 - Funding Information: This work was supported in part by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (nos. 2012R1A1A1013290, 2008-0061906, 2015R1A1A05001560, 2015R1A5A1009962, and 2008-0062257) and also by the Top Brand Project through a grant provided by the Gwangju Institute of Science and Technology in 2014. Work at Rutgers was supported by the Office of Naval Research (N000141210456). The work at POSTECH was supported by the NRF through the SRC Program (no. 2011-0030785). Publisher Copyright: © 2015, Hamh et al.

PY - 2015/12/1

Y1 - 2015/12/1

N2 - We investigate the surface states of topological insulator (TI) Bi2Se3 thin films grown on Si nanocrystals and Al2O3 substrates by using terahertz (THz) emission spectroscopy. Compared to bulk crystalline Bi2Te2Se, film TIs exhibit distinct behaviors in the phase and amplitude of emitted THz radiation. In particular, Bi2Se3 grown on Al2O3 shows an anisotropic response with a strong modulation of the THz signal in its phase. From x-ray diffraction, we find that the crystal plane of the Bi2Se3 films is inclined with respect to the plane of the Al2O3 substrate by about 0.27°. This structural anisotropy affects the dynamics of photocarriers and hence leads to the observed anisotropic response in the THz emission. Such relevance demonstrates that THz emission spectroscopy can be a sensitive tool to investigate the fine details of the surface crystallography and electrostatics of thin film TIs.

AB - We investigate the surface states of topological insulator (TI) Bi2Se3 thin films grown on Si nanocrystals and Al2O3 substrates by using terahertz (THz) emission spectroscopy. Compared to bulk crystalline Bi2Te2Se, film TIs exhibit distinct behaviors in the phase and amplitude of emitted THz radiation. In particular, Bi2Se3 grown on Al2O3 shows an anisotropic response with a strong modulation of the THz signal in its phase. From x-ray diffraction, we find that the crystal plane of the Bi2Se3 films is inclined with respect to the plane of the Al2O3 substrate by about 0.27°. This structural anisotropy affects the dynamics of photocarriers and hence leads to the observed anisotropic response in the THz emission. Such relevance demonstrates that THz emission spectroscopy can be a sensitive tool to investigate the fine details of the surface crystallography and electrostatics of thin film TIs.

KW - BiSe

KW - Terahertz emission

KW - Thin film

KW - Topological insulator

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