Surface and interface states of Bi2Se3 thin films investigated by optical second-harmonic generation and terahertz emission

S. Y. Hamh, S. H. Park, S. K. Jerng, J. H. Jeon, S. H. Chun, J. H. Jeon, S. J. Kahng, K. Yu, E. J. Choi, S. Kim, S. H. Choi, N. Bansal, S. Oh, Joonbum Park, Byung Woo Kho, Jun Sung Kim, J. S. Lee

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13 Citations (Scopus)

Abstract

We investigate the surface and interface states of Bi2Se3 thin films by using the second-harmonic generation technique. Distinct from the surface of bulk crystals, the film surface and interface show the isotropic azimuth dependence of second-harmonic intensity, which is attributed to the formation of randomly oriented domains on the in-plane. Based on the nonlinear susceptibility deduced from the model fitting, we determine that the surface band bending induced in a space charge region occurs more strongly at the film interface facing the Al2O3 substrate or capping layer compared with the interface facing the air. We demonstrate that distinct behavior of the terahertz electric field emitted from the samples can provide further information about the surface electronic state of Bi2Se3.

Original languageEnglish
Article number051609
JournalApplied Physics Letters
Volume108
Issue number5
DOIs
Publication statusPublished - 2016 Feb 1

Bibliographical note

Funding Information:
We would like to thank Jae Myung Kim, Okkyun Seo, Do Young Noh, Sungsu Lee, and Ji Young Jo for their contribution to X-ray diffraction measurement. This work was supported in part by the Science Research Center and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (Nos. 2015R1A5A1009962 and 2015R1A1A1A05001560) and also by the Top Brand Project through a grant provided by the Gwangju Institute of Science and Technology in 2015. The work at Sejong was also supported by NRF (Nos. 2010-0020207, 2011-0030786, and 2014R1A2A2A01005963). The work at Rutgers was supported by Office of Naval Research (N000141210456). The work at POSTECH was supported by the NRF through SRC (Grant No. 2011-0030785) and Max Planck POSTECH/KOREA Research Initiative Programs (Grant No. 2011-0031558).

Publisher Copyright:
© 2016 AIP Publishing LLC.

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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