제목 [2017.11.14][colloquium] 2D Semiconductor, Transition Metal Dichalcogenides Growth and Its Applications
작성자 물리학과홈피 등록일 2017-11-08 오후 6:47:07 조회수 162
추천 0 비추천 0
날짜 : 11월 14일 화요일
시간 : 오후 4시 30분
장소 : R404
연사 : 김용수 교수님 ( 울산대학교 물리학과 )
제목 : 2D Semiconductor, Transition Metal Dichalcogenides Growth and Its Applications
내용 : Graphene, a single atomic layer of carbon atoms, has attracted grated attention because of its novel physical properties and potential for electro-optical technology. Recently this interest has expanded to the wide class of two-dimensional materials that occur naturally as 2D layers of van-der-Waals crystals. While preserving graphene’s flexibility and tenability by external perturbations, atomically thin layers of this broader set of materials provide access to more varied electronic and optical properties, including semiconductor and insulating behavior. In first part of this presentation, I will discuss some distinctive properties and large area continuous growth of atomically thin 2D semiconductor, especially transition metal dichalcogenide (MX2 where M=Mo, W and X=Se, S) [1-3]. I also demonstrates monolayer Mo(S,Se)2 is next generation nonlinear optical material for its strong optical nonlinear properties with second harmonic generation characteristics [4-7]. In second part of this talk, I will demonstrate the in-plane heterostructure (HS) of monolayer MX2. From synthetic prospective, unlike vertical HS, the lateral HS can only be created by direct growth method. Here, I present the growth of three-atom-thick lateral HS consisting of MoSe2 and WSe2 monolayers by a pulsed-laser-deposition-assisted (PLD-assisted) selenization method. [2] The sharp interface of the grown monolayer lateral HS was verified by morphological and optical characterizations. Interestingly, the photoluminescence spectra acquired from the interface showed clear signatures of pristine MoSe2 and WSe2 with no intermediate energy peak related to the formation of the MoxW1-xSe2 alloy or excitonic matter across the HS, thereby confirming the sharp interface [8].
[1] V. Senthilkumar et al., Nano Res. 7, 1759 (2014)
[2] F. Ullah et al., CrystEngComm 18, 6992 (2016),
[3] H. G. Park et al., Appl. Spectrosc. Rev. 51, 621 (2016)
[4] D. J. Clark et al., Phys. Rev. B 90, 121409(R) (2014); 92, 159901(E) (2015)
[5] D. J. Clark et al., Appl. Phys. Lett. 107, 131113 (2015)
[6] C. T. Le et al., Ann. Phys. 528, 551 (2016)
[7] C. T. Le et al., ACS Photonics 4, 38-44 (2017)
[8] F. Ullah et al., ACS Nano 11, 8822 (2017),

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