Optical and valleytronic hysteresis of IXs in WS2/WSe2 heterostructure (IMAGE)

Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, CAS

Optical and valleytronic hysteresis of IXs in WS2/WSe2 heterostructure

Caption

a, Schematic of the device which is composed by a WS2/WSe2 heterostructure on a oxygen-plasma cleaned SiO2/Si substrate. b-c, Photon energy and absolute circular polarization degree of the IXs as a function of Vg, showing a large hysteresis. d, PL spectra of the IXs at 0 V with different scanning sequences (0V-1 ~ -60 V ~ 0V-2 ~ 60 V ~ 0V-3). The 0V-2 spectrum blueshifts for about 20 meV in comparison to 0V-1 and 0V-3. e-f, Schematic of the origin of the hysteresis effect. Chemical-doped electrons lift the Fermi level up and shift IXs from spin-triplet state (IXS) to spin-singlet state (IXT). When those electrons are released, the IXs return from IXT to IXS. The orange dashed line stands for the upper spin-splitting conduction band (CB) of WS2. Red and blue arrows represent the recombination paths of the IXs.

Credit

by Tong Ye, Yongzhuo Li, Junze Li, Hongzhi Shen, Junwen Ren, Cun-Zheng Ning, Dehui Li

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License

CC BY

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