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Title: Spectroscopic ellipsometry-based study of optical properties of amorphous and crystalline ZnSnO alloys and Zn{sub 2}SnO{sub 4} thin films grown using sputtering deposition: Dielectric function and subgap states

Abstract

We investigated the optical properties of amorphous and crystalline zinc tin oxide (ZTO) thin films grown on SiO{sub 2}/Si substrates with varying compositions via a co-sputtering deposition method at room temperature. The co-sputtering targets consist of SnO{sub 2} and ZnO. By varying the relative power ratio of the two targets, we demonstrate the ability to control the Sn and Zn composition of the resulting ZTO thin films. The ratio of [Sn]/([Sn] + [Zn]) atomic compositions was estimated at 11%, 29%, 42%, 54%, and 60%. Using a 600 °C annealing process, the as-grown amorphous ZTO films were transformed into crystalline ZTO films. The dielectric functions were obtained based on the measured ellipsometric angles, ψ and Δ. We determined the dielectric functions, absorption coefficients, and optical gap energies of ZTO thin films with varying compositions. The dielectric functions, absorption coefficients, and optical gap energies of amorphous and crystalline Zn{sub 2}SnO{sub 4} thin films were obtained at 29 at. % of Sn. Subgap states at 1.6 eV (A) and 2.8 eV (B) of ZnSnO alloys and Zn{sub 2}SnO{sub 4} films were found in the imaginary part of the dielectric function spectra. The subgap state intensities were reduced via a nitrogen gas annealing. Possible origins of the observed subgap states willmore » be discussed.« less

Authors:
; ; ; ;  [1]
  1. Department of Applied Physics and Institute of Natural Sciences, Kyung Hee University, Yong-In 17104 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22594562
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 13; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; AMORPHOUS STATE; ANNEALING; DEPOSITION; DIELECTRIC MATERIALS; ELLIPSOMETRY; NITROGEN; OPTICAL PROPERTIES; SILICA; SILICON OXIDES; SPUTTERING; SUBSTRATES; THIN FILMS; TIN ALLOYS; TIN OXIDES; ZINC ALLOYS; ZINC OXIDES

Citation Formats

Ko, Kun Hee, So, Hyeon Seob, Jung, Dae Ho, Park, Jun Woo, and Lee, Hosun, E-mail: hlee@khu.ac.kr. Spectroscopic ellipsometry-based study of optical properties of amorphous and crystalline ZnSnO alloys and Zn{sub 2}SnO{sub 4} thin films grown using sputtering deposition: Dielectric function and subgap states. United States: N. p., 2016. Web. doi:10.1063/1.4945316.
Ko, Kun Hee, So, Hyeon Seob, Jung, Dae Ho, Park, Jun Woo, & Lee, Hosun, E-mail: hlee@khu.ac.kr. Spectroscopic ellipsometry-based study of optical properties of amorphous and crystalline ZnSnO alloys and Zn{sub 2}SnO{sub 4} thin films grown using sputtering deposition: Dielectric function and subgap states. United States. doi:10.1063/1.4945316.
Ko, Kun Hee, So, Hyeon Seob, Jung, Dae Ho, Park, Jun Woo, and Lee, Hosun, E-mail: hlee@khu.ac.kr. Thu . "Spectroscopic ellipsometry-based study of optical properties of amorphous and crystalline ZnSnO alloys and Zn{sub 2}SnO{sub 4} thin films grown using sputtering deposition: Dielectric function and subgap states". United States. doi:10.1063/1.4945316.
@article{osti_22594562,
title = {Spectroscopic ellipsometry-based study of optical properties of amorphous and crystalline ZnSnO alloys and Zn{sub 2}SnO{sub 4} thin films grown using sputtering deposition: Dielectric function and subgap states},
author = {Ko, Kun Hee and So, Hyeon Seob and Jung, Dae Ho and Park, Jun Woo and Lee, Hosun, E-mail: hlee@khu.ac.kr},
abstractNote = {We investigated the optical properties of amorphous and crystalline zinc tin oxide (ZTO) thin films grown on SiO{sub 2}/Si substrates with varying compositions via a co-sputtering deposition method at room temperature. The co-sputtering targets consist of SnO{sub 2} and ZnO. By varying the relative power ratio of the two targets, we demonstrate the ability to control the Sn and Zn composition of the resulting ZTO thin films. The ratio of [Sn]/([Sn] + [Zn]) atomic compositions was estimated at 11%, 29%, 42%, 54%, and 60%. Using a 600 °C annealing process, the as-grown amorphous ZTO films were transformed into crystalline ZTO films. The dielectric functions were obtained based on the measured ellipsometric angles, ψ and Δ. We determined the dielectric functions, absorption coefficients, and optical gap energies of ZTO thin films with varying compositions. The dielectric functions, absorption coefficients, and optical gap energies of amorphous and crystalline Zn{sub 2}SnO{sub 4} thin films were obtained at 29 at. % of Sn. Subgap states at 1.6 eV (A) and 2.8 eV (B) of ZnSnO alloys and Zn{sub 2}SnO{sub 4} films were found in the imaginary part of the dielectric function spectra. The subgap state intensities were reduced via a nitrogen gas annealing. Possible origins of the observed subgap states will be discussed.},
doi = {10.1063/1.4945316},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 13,
volume = 119,
place = {United States},
year = {2016},
month = {4}
}