Engineering fluorescence intensity and electron concentration of monolayer MoS2 by forming heterostructures with semiconductor dots

• Published in: Nanoscale Vol. 11; no. 14; pp. 6544 - 6551
• Main Authors: Feng, Qiushi, Shi, Jia, Yang, Weiqiang, Zhong, Weiheng, Li, Yuanzheng, Chen, Heyu, Liu, Weizhen, Xu, Haiyang, Liu, Xinfeng, Liu, Yichun
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 14.04.2019
• Subjects: Carbon; Carbon dots; Carrier density; Charge transfer; Decoration; Doping; Electron transfer; Electrons; Fluorescence; Heterostructures; Molybdenum disulfide; Monolayers; Photoelectrons; Photoluminescence; Zinc oxide
• ISSN: 2040-3364; 2040-3372; 2040-3372
• DOI: 10.1039/c8nr08209j

In this work, novel 2D/0D hybrid heterostructures with facilely adjustable fluorescence intensity and carrier concentration are achieved by decorating monolayer MoS2 (1L-MoS2) flakes with semiconductor-dots (carbon-dots or ZnO-dots). By carbon-dot decoration, the fluorescence intensity of 1L-MoS2 is significantly suppressed due to the n-type doping effect of electron transfer from carbon-dots to 1L-MoS2. In contrast, 1L-MoS2 decorated with ZnO-dots exhibits remarkably enhanced photoluminescence, because of the effective p-type doping modulation of electron transfer from 1L-MoS2 to ZnO-dots. The different charge transfer directions lie in the distinct energy band alignment of the two heterostructures. Raman, time-resolved photoluminescence and X-ray photoelectron spectroscopy studies prove the effective charge transfer between 1L-MoS2 and carbon-dots/ZnO-dots. Semi-quantitative estimations based on a mass-action-model demonstrate that the electron concentration in 1L-MoS2 can be controllably tuned from 1012 to 1014 cm−2via the p-type/n-type doping effect of these hybrid heterostructures.