Significant Exciton Brightening in Monolayer Tungsten Disulfides via Fluorination: n-Type Gas Sensing Semiconductors

Title
Significant Exciton Brightening in Monolayer Tungsten Disulfides via Fluorination: n-Type Gas Sensing Semiconductors
Authors
전영민김재헌이택진서민아전영인Younghee KimJune Park
Keywords
WTe2; gas sensing; Exciton
Issue Date
2016-11
Publisher
Advanced functional materials
Citation
VOL 26, NO 42-7559
Abstract
Monolayer transition-metal dichalcogenides (TMDCs) have recently emerged as promising candidates for advanced photonic and valleytronic applications due to their unique optoelectronic properties. However, the low luminescence efficiency of monolayer TMDCs has significantly hampered their use in these fields. Here it is reported that the photoluminescence efficiency of monolayer WS2 can be remarkably enhanced up to fourfold through the fluorination, surpassing the reported performance of molecular and/or electrical doping methods. Its degree is easily controlled by changing the fluorine plasma duration time and can also be reversibly tuned via additional hydrogen plasma treatment, allowing for its versatile tailoring for interfacial band alignment and customized engineering. The striking photoluminescence improvement occurs via a substantial transition of trions to excitons as a result of the strong electron affinity of fluorine dopants, and the fluorination enables unprecedented detection of n-type NH3 gas in WS2 due to changed excitonic dynamics showing excellent sensitivity (at least down to 1.25 ppm). This work provides valuable strategies and insights into exciton physics in monolayer TMDCs, opening up avenues toward highly-efficient 2D light emitters, photovoltaics, nanosensors, and optical interconnects.
URI
http://pubs.kist.re.kr/handle/201004/64846
ISSN
1616-301X
Appears in Collections:
KIST Publication > Article
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