標題: Photoluminescence Enhancement and Structure Repairing of Monolayer MoSe2 by Hydrohalic Acid Treatment
作者: Han, Hau-Vei
Lu, Ang-Yu
Lu, Li-Syuan
Huang, Jing-Kai
Li, Henan
Hsu, Chang-Lung
Lin, Yung-Chang
Chiu, Ming-Hui
Suenaga, Kazu
Chu, Chih-Wei
Kuo, Hao-Chung
Chang, Wen-Hao
Li, Lain-Jong
Shi, Yumeng
電子物理學系
光電工程學系
Department of Electrophysics
Department of Photonics
關鍵字: transition-metal dichalcogenides;molybdenum diselenide;layered materials;photoluminescence;two-dimensional materials
公開日期: 1-Jan-2016
摘要: Atomically thin two-dimensional transition metal dichalcogenides (TMDCs) have attracted much attention recently due to their unique electronic and optical properties for future optoelectronic devices. The chemical vapor deposition (CVD) method is able to generate TMDCs layers with a scalable size and a controllable thickness. However, the TMDC monolayers grown by CVD may incorporate structural defects, and it is fundamentally important to understand the relation between photoluminescence and structural defects. In this report, point defects (Se vacancies) and oxidized Se defects in CVD-grown MoSe2 monolayers are identified by transmission electron microscopy and X-ray photoelectron spectroscopy. These defects can significantly trap free charge carriers and localize excitons, leading to the smearing of free band-to-band exciton emission. Here, we report that the simple hydrohalic acid treatment (such as HBr) is able to efficiently suppress the trap state emission and promote the neutral exciton and trion emission in defective MoSe2 monolayers through the p-doping process, where the overall photoluminescence intensity at room temperature can be enhanced by a factor of 30. We show that HBr treatment is able to activate distinctive trion and free exciton emissions even from highly defective MoSe2 layers. Our results suggest that the HBr treatment not only reduces the n-doping in MoSe2 but also reduces the structural defects. The results provide further insights of the control and tailoring the exciton emission from CVD-grown monolayer TMDCs.
URI: http://dx.doi.org/10.1021/acsnano.5b06960
http://hdl.handle.net/11536/129688
ISSN: 1936-0851
DOI: 10.1021/acsnano.5b06960
期刊: ACS NANO
Volume: 10
起始頁: 1454
結束頁: 1461
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