J
Junfeng Dai
Researcher at Southern University of Science and Technology
Publications - 53
Citations - 6401
Junfeng Dai is an academic researcher from Southern University of Science and Technology. The author has contributed to research in topics: Spintronics & Medicine. The author has an hindex of 20, co-authored 46 publications receiving 5174 citations. Previous affiliations of Junfeng Dai include South University of Science and Technology of China & University of Hong Kong.
Papers
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Journal ArticleDOI
Valley polarization in MoS2 monolayers by optical pumping
TL;DR: It is demonstrated that optical pumping with circularly polarized light can achieve a valley polarization of 30% in pristine monolayer MoS(2), demonstrating the viability of optical valley control and valley-based electronic and optoelectronic applications in MoS (2) monolayers.
Journal ArticleDOI
Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides
Hualing Zeng,Gui-Bin Liu,Gui-Bin Liu,Junfeng Dai,Junfeng Dai,Yajun Yan,Bairen Zhu,Ruicong He,Lu Xie,Shijie Xu,Xianhui Chen,Wang Yao,Xiaodong Cui +12 more
TL;DR: In this article, optical studies of WS2 and WSe2 monolayers and multilayers were carried out, and it was shown that second harmonic generation shows a dramatic evenodd oscillation with the number of layers, consistent with the presence (absence) of inversion symmetry in even-layer (odd-layer).
Journal ArticleDOI
Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides
Hualing Zeng,Gui-Bin Liu,Gui-Bin Liu,Junfeng Dai,Junfeng Dai,Yajun Yan,Bairen Zhu,Ruicong He,Lu Xie,Shijie Xu,Xianhui Chen,Wang Yao,Xiaodong Cui +12 more
TL;DR: The efficiency of second harmonic generation shows a dramatic even-odd oscillation with the number of layers, consistent with the presence (absence) of inversion symmetry in even-layer (odd-layer) and the giant spin-valley coupling which fully suppresses interlayer hopping at valence band edge near K points.
Journal ArticleDOI
Is Excess PbI2 Beneficial for Perovskite Solar Cell Performance
Fangzhou Liu,Qi Dong,Man Kwong Wong,Aleksandra B. Djurišić,Annie Ng,Zhiwei Ren,Qian Shen,Charles Surya,Wai Kin Chan,Jian Wang,Alan Man Ching Ng,Changzhong Liao,Hangkong Li,Kaimin Shih,Chengrong Wei,Huimin Su,Junfeng Dai +16 more
TL;DR: In this paper, it was shown that the presence of unreacted PbI2 results in an intrinsic instability of the perovskite film under illumination, leading to the film degradation under inert atmosphere and faster degradation upon exposure to illumination and humidity.
Journal ArticleDOI
Anomalously robust valley polarization and valley coherence in bilayer WS2
TL;DR: In this paper, the authors reported the anomalously robust valley polarization and valley coherence in bilayer WS2 and showed that the photoluminescence from WS2 follows that of the excitation source with both circular and linear polarization, and remains even at room temperature.