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|
| Type |
Poster Presentation |
| Area |
Physical Chemistry |
| Room No. |
Grand Ballroom |
| Time |
10월 19일 (금요일) 11:00~12:30 |
| Code |
PHYS.P-195 |
| Subject |
Twist-angle dependent optical second-harmonic generation from MoS2/WS2 heterostructure |
| Authors |
Wontaek Kim, Sunmin Ryu*
Department of Chemistry, Pohang University of Science and Technology, Korea
|
| Abstract |
Optical second-harmonic generation (SHG) by single and few-layer transition metal dichalcogenides (TMD) is highly efficient and sensitive to their structural symmetry. Recently, it was reported that the SHG signal from artificially-stacked MoS2 (molybdenum disulfide) bilayers can be understood as superposition of SHG fields from the individual layers. However, it has not been verified whether this model is still valid for TMD heterostructures. In this work, we studied SHG behavior of artificially-stacked MoS2/WS2 (tungsten disulfide) hetero-bilayers of varing twist angle in comparison with MoS2 homo-bilayers. Polarization-resolved SHG polar plots from MoS2 homo-bilayers exhibited a six-petal pattern like those from MoS2 monolayer. Remarkably, we found that polarization-resolved SHG behavior of MoS2/WS2 is much different from that of MoS2 bilayers. Unlike the homo-bilayers, the hetero-bilayers exhibited constant background signal in addition to the six-petal pattern. This anomalous background became bigger for more staggered hetero-bilayers. To explain these results, we propose that the anomaly originates from SHG phase difference between MoS2 and WS2, and will corroborate its validity with phase-resolved SHG measurements and numerical simulations. |
| E-mail |
kwt2015@postech.ac.kr |
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122nd General Meeting of the KCS