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    学术讲座(六十二):Optical probing strong light-matterinteractions in 2D materials

    2018-11-26

     

     

    主讲人: Ting Yu教授

    时间: 20181125日上午9:00-10:00

    地点: 深圳大学西丽校区420会议室

    报告人简介:

    Dr. Ting YU received his PhD inDepartment of Physics, National University of Singapore in 2003 and iscurrently a Professor in Division of Physics and Applied Physics, NanyangTechnological University, Singapore. Dr. YU has received many prestigiousawards including Nanyang Excellence Award for Research and Innovation (2008),National Young Scientist Award, National Research Foundation Fellowship Award(2009), Outstanding Young Scientist for the 3rd Inter Academy Panel/WorldEconomic Forum (Summer Davos Forum) ((IAP/WEF, Representative of Singapore,2010) and Institute of Physics Singapore, Nanotechnology award (2011). Hisresearch interests cover fabrication of low dimensional, especially 2Dmaterials and investigation of their optical, optoelectrical and eletrochemicalproperties for developing novel electronics, optoelectronics and energy conversion/storage.Dr Yu has published more than 260 SCI papers and received over 18,000nonself-citations. His H-index is 72.

    讲座摘要:

    Two-dimensional (2D) materials, suchas graphene and monolayer transitional-metal-dichalcogenides (TMDs), havearoused great attention due to the underlying fundamental physics and thepromising atomically-thin optoelectronic applications. Optical properties ofthese 2D materials are fundamentally interesting such as magneto-phononresonance in graphene and strong excitonic emission in monolayer WS2.Meanwhile, development of practical optoelectronics based on 2D materials isvery promising, which opens many opportunities for the next-generationlight-emitting applications such as valley light-emitting diodes and on-chipvertical-cavity surface-emitting lasers (VCSELs). Here, we report observationsof magneto-phonon coupling effects in graphene layers, wealthy excitonicemission states of monolayer WS2, and 2D semiconductor lasing from monolayerWS2 embedded VCSELs. In particular, the triple G-mode splitting in graphene ongraphite and the magnetic oscillations of the G-mode phonons in ABA- and ABC-stackedtrilayer graphene samples have been probed by custom-designed micro-magnetoRaman spectroscopy. By electrostatic and optical doping, tunable excitonicemission has been achieved due to interplay of various excitonic states.Meanwhile, the doping dependences of excitons, trions, biexcitons and diversebound excitons associated with impurities and structural defects have beendiscussed. Furthermore, we realize room-temperature low-threshold lasing frommonolayer WS2 activated VCSELs under continuous-wave optical pumping, which areintrinsically compatible with the prevailing monolithic integration technology.Overall, our studies provide many new understandings on fundamentallight-matter interactions in atomically thin materials and pave ways to developindustrially attractive light-emitting applications based on 2D semiconductors.

     

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