Title: Atomic layer oxidation on graphene sheets for tuning their oxidation levels, electrical conductivities, and band gaps

Abstract

Graphene sheets that can exhibit electrical conducting and semiconducting properties are highly desirable and have potential applications in fiber communications, photodetectors, solar cells, semiconductors, and broadband modulators. However, there is currently no efficient method that is able to tune the band gap of graphene sheets. This paper adopts an efficient atomic layer oxidation (ALO) technique to cyclically increase the oxidation level of graphene sheets, thus, tuning their electrical conductance, band-gap structure, and photoluminescence (PL) response. The O/C atomic ratio as an increasing function of the ALO cycle number reflects two linear regions: 0.23% per cm ² per cycle (0–15 cycles) and 0.054% per cm ² per cycle (15–100 cycles). The excellent correlation coefficients reveal that the ALO process follows a self-limiting route to step-by-step oxidize graphene layers. The interlayer distance of ALO-graphene sheets shows an obvious increase after the ALO treatment, proved by X-ray diffraction. As analyzed by X-ray photon spectroscopy, the hydroxyl or epoxy group acts as a major contributor to the interlayer spacing distance and oxidation extent in the initial ALO stage, as compared to carbonyl and carboxyl groups. The ALO mechanism, based on Langmuir–Hinshelwood and Eley–Rideal models, is proposed to clarify the formation of oxygen functionalities andmore » structural transformation from pristine graphene sheets to oxidized ones during the ALO cycle. With a tunable oxidation level, the electrical resistivity, semiconductor character, and PL response of ALO-graphene samples can be systematically controlled for desired applications. Finally, the ALO approach is capable of offering a straightforward route to tune the oxidation level of graphene sheets or other carbons.« less

Authors:

Gu, Siyong  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3963-4644"
• Search orcid.org for ORCID "0000-0003-3963-4644"

Hsieh, Chien-Te  ^[2];

• Search DOE PAGES for author "Hsieh, Chien-Te"
• Search DOE PAGES for ORCID "0000-0002-1053-8635"
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Lin, Tzu-Wei ^[3]; Yuan, Chun-Yao ^[3]; Ashraf Gandomi, Yasser ^[4]; Chang, Jeng-Kuei  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-8359-5817"
• Search orcid.org for ORCID "0000-0002-8359-5817"

Li, Jianlin  ^[6]

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• Search DOE PAGES for ORCID "0000-0002-8710-9847"
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+ Show Author Affiliations

1. Xiamen Univ. of Technology (China). Fujian Provincial Key Lab. of Functional Materials and Applications. Inst. of Material Preparation and Applied Technology. School of Materials Science and Engineering
2. Yuan Ze Univ., Taoyuan (Taiwan). Dept. of Chemical Engineering and Materials Science; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical, Aerospace, and Biomedical Engineering
3. Yuan Ze Univ., Taoyuan (Taiwan). Dept. of Chemical Engineering and Materials Science
4. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical, Aerospace, and Biomedical Engineering
5. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Nuclear Science and Engineering. Dept. of Materials Science and Engineering; National Chiao Tung Univ., Hsinchu (Taiwan). Dept. of Materials Science and Engineering
6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division

Publication Date:

2018-07-24

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yuan Ze Univ., Taoyuan (Taiwan); National Chiao Tung Univ., Hsinchu (Taiwan)

Sponsoring Org.:

USDOE; Ministry of Science and Technology of Taiwan

OSTI Identifier:

1468151

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Nanoscale

Additional Journal Information:

Journal Volume: 10; Journal Issue: 33; Journal ID: ISSN 2040-3364

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE