Title: High Luminescence Efficiency in MoS₂ Grown by Chemical Vapor Deposition

Abstract

We report that one of the major challenges facing the rapidly growing field of two-dimensional (2D) transition metal dichalcogenides (TMDCs) is the development of growth techniques to enable large-area synthesis of high-quality materials. Chemical vapor deposition (CVD) is one of the leading techniques for the synthesis of TMDCs; however, the quality of the material produced is limited by defects formed during the growth process. A very useful nondestructive technique that can be utilized to probe defects in semiconductors is the room-temperature photoluminescence (PL) quantum yield (QY). It was recently demonstrated that a PL QY near 100% can be obtained in MoS₂ and WS₂ monolayers prepared by micromechanical exfoliation by treating samples with an organic superacid: bis(trifluoromethane)sulfonimide (TFSI). Here we have performed a thorough exploration of this chemical treatment on CVD-grown MoS₂ samples. We find that the as-grown monolayers must be transferred to a secondary substrate, which releases strain, to obtain high QY by TFSI treatment. Furthermore, we find that the sulfur precursor temperature during synthesis of the MoS₂ plays a critical role in the effectiveness of the treatment. By satisfying the aforementioned conditions we show that the PL QY of CVD-grown monolayers can be improved from ~0.1% in the as-grownmore » case to ~30% after treatment, with enhancement factors ranging from 100 to 1500× depending on the initial monolayer quality. We also found that after TFSI treatment the PL emission from MoS₂ films was visible by eye despite the low absorption (5–10%). Lastly, the discovery of an effective passivation strategy will speed the development of scalable high-performance optoelectronic and electronic devices based on MoS₂.« less

Authors:

Amani, Matin ^[1]; Burke, Robert A. ^[2]; Ji, Xiang ^[3]; Zhao, Peida ^[1]; Lien, Der-Hsien ^[1]; Taheri, Peyman ^[4]; Ahn, Geun Ho ^[1]; Kirya, Daisuke ^[1]; Ager, Joel W. ^[5]; Yablonovitch, Eli ^[1]; Kong, Jing ^[3]; Dubey, Madan ^[2]; Javey, Ali ^[1]

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Army Research Lab., Adelphi, MD (United States)
3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
4. Univ. of California, Berkeley, CA (United States)
5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

Sat Jun 11 00:00:00 EDT 2016

Research Org.:

Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division

OSTI Identifier:

1557789

Grant/Contract Number:  

SC0001088; AC02-05CH11231; SC0004993

Resource Type:

Accepted Manuscript

Journal Name:

ACS Nano

Additional Journal Information:

Journal Volume: 10; Journal Issue: 7; Journal ID: ISSN 1936-0851

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; transition metal dichalcogenide; MoS2; chemical vapor deposition; quantum yield; radiative lifetime; biexcitonic recombination