摘要
Mixed dimensional van der Waals(VdW)heterostructures constructed by one-dimensional(1D)and two-dimensional(2D)materials exhibit extra degree of freedom to modulate the electronic and optical properties due to the combination of difterent dimensionalities.The charge transfer at the intertace between 1D and 2D materials plays a crucial role in the optoelectronic properties and performance of the heterostructure-based devices.Here,we stacked single-walled carbon nanotubes(SWNTs)on monolayer WS2 for a mixed dimensional vdW heterostructure,and investigated the local modulation of excitions and trions in WS2 by SWNTs.Different directions of charge transfer between SWNTs and WSz are evidenced by the photoluminescence(PL)spectra of WS2.The PL intensity can be either enhanced or weakened by individual SWNTs.In our work,the PL intensity of WS2 is enhanced and the exciton peak position heterostructure is red-shifted about 3 meV due to the charge transfer from WS2 to an individual SWNT(SWNT#1).The change of PL by another SWNT(SWNT#2)can not be well-resolved in far fild,but scanning near field optical microscope(SNOM)measurements show that the PL intensity of WS2 is weakened by the SWNT.The peak position of exciton is blue-shifted by^1 meV while that of trion is redshifted by^1 meV due to the charge transfer from the SWNT to WS2,These results give insight into the charge transfer at the interface of SWNTWS2 heterostructure,and can be useful for design of optoelectronic devices based on mixed dimensional vdW heterostructures.
基金
the National Basic Research Program of China(Nos.2018YFA0703502 and 2016YFA0200104)
the National Natural Science Foundation of China(Nos.51720105003,21790052,21573004 and 21974004).
