Duan Research Group

Hetero-integrated Nanostructures and Nanodevices


Enhanced interlayer neutral excitons and trions in trilayer van der Waals heterostructures

Chanyeol Choi, Jiahui Huang, Hung-Chieh Cheng, Hyunseok Kim, Abhinav Kumar Vinod, Sang-Hoon Bae, V Ongun Özçelik, Roberto Grassi, Jongjae Chae, Shu-Wei Huang, Xiangfeng Duan, Kristen Kaasbjerg, Tony Low, Chee Wei Wong

npj 2D Materials and Applications 2, 30 (2018)

Vertically stacked van der Waals heterostructures constitute a promising platform for providing tailored band alignment with enhanced excitonic systems. Here, we report observations of neutral and charged interlayer excitons in trilayer WSe2–MoSe2–WSe2 van der Waals heterostructures and their dynamics. The addition of a WSe2 layer in the trilayer leads to significantly higher photoluminescence quantum yields and tunable spectral resonance compared to its bilayer heterostructures at cryogenic temperatures. The observed enhancement in the photoluminescence quantum yield is due to significantly larger electron–hole overlap and higher light absorbance in the trilayer heterostructure, supported via first-principles pseudopotential calculations based on spin-polarized density functional theory. We further uncover the temperature- and power-dependence, as well as time-resolved photoluminescence of the trilayer heterostructure interlayer neutral excitons and trions. Our study elucidates the prospects of manipulating light emission from interlayer excitons and designing atomic heterostructures from first-principles for optoelectronics.
UCLA, Department of Chemistry and Biochemistry
607 Charles E. Young Drive East, Box 951569
Los Angeles, CA 90095-1569
E-mail: xduan@chem.ucla.edu