High Luminescence Efficiency in MoS<sub>2</sub> Grown by Chemical Vapor Deposition

Amani, Matin; Burke, Robert A.; Ji, Xiang; Zhao, Peida; Lien, Der Hsien; Taheri, Peyman; Ahn, Geun Ho; Kirya, Daisuke; Ager, Joel W.; Yablonovitch, Eli; Kong, Jing; Dubey, Madan; Javey, Ali

doi:10.1021/acsnano.6b03443

Cited by 156 publications

(170 citation statements)

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“…36 In fact, the activity of those defect states can be diminished using a nonoxidizing organic superacid, such as bis(trifluoromethane)sulfonimide, providing a drastic enhancement of the PL emission. 40,41 Thus, to reaffirm that the decreased PL intensity in our hexagonal crystal originates from defects, we dipped the samples in a bis(trifluoromethane)sulfonimide solution for 1 h and found that the PL emissions drastically recovered in both the triangles and hexagons. The degree of enhancement was more severe in the hexagon than the triangle, implying that more defect states initially existed in the hexagonal MoS 2 crystals.…”

Section: Synthesis Of Multi-stacked Mos 2 Crystalsmentioning

confidence: 58%

Stacking-controllable interlayer coupling and symmetric configuration of multilayered MoS2

et al. 2018

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The stacking order in layered transition-metal dichalcogenides (TMDCs) induces variations in the electronic and interlayer couplings. Therefore, controlling the stacking orientations when synthesizing TMDCs is desirable but remains a significant challenge. Here, we developed and showed the growth kinetics of different shapes and stacking orders in as-grown multi-stacked MoS 2 crystals and revealed the stacking-order-induced interlayer separations, spin-orbit couplings (SOCs), and symmetry variations. Raman spectra in AA(A…)-stacked crystals demonstrated blueshifted out-of-plane (A 1g ) and in-plane (E 2g 1 ) phonon frequencies, representing a greater reduction of the van der Waals gap compared to conventional AB(A…)-stacking. Our observations, together with first-principles calculations, revealed distinct excitonic phenomena due to various stacking orientations. As a result, the photoluminescence emission was improved in the AA(A…)-stacking configuration. Additionally, calculations showed that the valence-band maxima (VBM) at the K point of the AA(A…)-stacking configuration was separated into multiple sub-bands, indicating the presence of stronger SOC. We demonstrated that AA(A…)-stacking emitted an intense second-harmonic signal (SHG) as a fingerprint of the more augmented non-centrosymmetric stacking and enabled SOC-induced splitting at the VBM. We further highlighted the superiority of four-wave mixing-correlated SHG microscopy to quickly resolve the symmetries and multi-domain crystalline phases of differently shaped crystals. Our study based on crystals with different shapes and multiple stacking configurations provides a new avenue for development of future optoelectronic devices.

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Section: Synthesis Of Multi-stacked Mos 2 Crystalsmentioning

confidence: 58%

Stacking-controllable interlayer coupling and symmetric configuration of multilayered MoS2

et al. 2018

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“…The high absorbance values underline the strong light matter interaction of SC-TMDs even in the monolayer limit with a thickness of less than 1 nm as it has been reported by several theoretical and experimental studies, too [14,22,26,27,[45][46][47][48]122,124,128,130] . The sizeable reduction of the absorbance for monolayers on a substrate points to the fact that the optical response can be significantly altered just by modification of substrate or environment by dielectric engineering and screening effects [38,62,63,65,74,89,127,[131][132][133] . The strong influence of the environment on the light-matter interaction of atomically thin semiconducting membranes motivates a great potential not only for sensing applications, but also for novel device architectures with precisely tailorable optical properties.…”

Section: From the Extinction Coefficient In The Visible Range Displaymentioning

confidence: 99%

“…SC-TMDs possess outstanding electronic [6,7,16,19,20] , excitonic [21][22][23][24][25][26][27] , mechanical [28] as well as fascinating spin-and valley [29][30][31][32] properties. SC-TMDs feature also various exotic properties including as single photon emission in WSe2 at low temperatures [33][34][35][36][37] , photoluminescence efficiency with near unity quantum yield achieved by chemical treatment of sulfur-based SC-TMDs [38,39] , layer-dependent superconductivity in highly doped MoS2 [40][41][42][43][44] to name just a view. In addition, more technology relevant characteristics are outstanding FET performance [16] , high sunlight absorbance of up to 15% in the visible range [45][46][47] , ultrahigh photosensitivity [48][49][50] , catalytic activity [51,52] and photocatalytic stability in aqueous electrolytes [53] making the material not only interesting to replace silicon in electronics but also as photo-catalyst e.g.…”

Section: General Introduction To 2d Materials and In Particular Semicmentioning

confidence: 99%

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Wurstbauer¹,

Miller²,

Parzinger³

et al. 2017

J. Phys. D: Appl. Phys.

110

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Abstract:The investigation of two-dimensional van der Waals materials is a vibrant, fast moving and still growing interdisciplinary area of research. Two-dimensional van der Waals materials are truly two-dimensional crystals with strong covalent in-plane bonds and weak van der Waals interaction between the layers with a variety of different electronic, optical and mechanical properties. A very prominent class of twodimensional materials are transition metal dichalcogenides and amongst them particularly the semiconducting subclass. Their properties include bandgaps in the near-infrared to the visible range, decent charge carrier mobility together with high (photo-)catalytic and mechanical stability and exotic many body phenomena. These characteristics make the materials highly attractive for both fundamental research as well as innovative device applications. Furthermore, the materials exhibit a strong light matter interaction providing a high sun light absorbance of up to 15% in the monolayer limit, strong scattering cross section in Raman experiments and access to excitonic phenomena in van der Waals heterostructures. This review focuses on the light matter interaction in MoS2, WS2, MoSe2, and WSe2 that is dictated by the materials complex dielectric functions and on the multiplicity of studying the first order phonon modes by Raman spectroscopy to gain access to several material properties such as doping, strain, defects and temperature. Two-dimensional materials provide an interesting platform to stack them into van der Waals heterostructures without the limitation of lattice mismatch resulting in novel devices for application but also to study exotic many body interaction phenomena such as interlayer excitons. Future perspectives of semiconducting transition metal dichalcogenides and their heterostructures for applications in optoelectronic devices will be examined and routes to study emergent fundamental problems and manybody quantum phenomena under excitations with photons will be discussed.

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“…In monolayer MoS 2 (thickness ≈0.6 nm), the band gap becomes direct with a width of 1.8 eV. [1] Importantly, to meet the requirements of different applications, properties of MoS 2 and other TMDCs can be tuned by controlling the thickness, [1] doping and alloying, [5][6][7][8] surface modification and functionalization, [9][10][11] strain, [12,13] and by creating heterostructures with other 2D materials. [6,[14][15][16] The appealing properties of TMDCs have led to a wide range of proposed applications.…”

mentioning

confidence: 99%

Atomic Layer Deposition of Crystalline MoS₂ Thin Films: New Molybdenum Precursor for Low‐Temperature Film Growth

Mattinen

Hatanpää

Sarnet

et al. 2017

Adv Materials Inter

111

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Compared to the most well-known 2D material, graphene, which is a semi-metal, the semiconducting 2H phase of MoS 2 is advantageous in having a band gap suitable for electronic applications. In bulk form, MoS 2 has an indirect band gap of 1.3 eV, which increases as a function of decreasing film thickness. In monolayer MoS 2 (thickness ≈0.6 nm), the band gap becomes direct with a width of 1.8 eV. [1] Importantly, to meet the requirements of different applications, properties of MoS 2 and other TMDCs can be tuned by controlling the thickness, [1] doping and alloying, [5][6][7][8] surface modification and functionalization, [9][10][11] strain, [12,13] and by creating heterostructures with other 2D materials. [6,[14][15][16] The appealing properties of TMDCs have led to a wide range of proposed applications. MoS 2 has been extensively studied as a channel material in conventional field-effect transistors, [17][18][19][20][21] as well as phototransistors and other optoelectronic devices. [16,21,22] The 2D structure of TMDCs plays a crucial role in possible applications relying on more exotic quantum phenomena, such as valleytronics. [23,24] MoS 2 has also shown promise in, for example, catalysis, [25] batteries, [26] photovoltaics, [27] sensors, [28] and medicine. [29] The production of high-quality, large-area MoS 2 films with a thickness controllable down to a monolayer, as required in many of the aforementioned applications, still remains a major challenge. Additionally, in many cases, the processing temperature should be kept as low as possible in order to avoid damaging sensitive substrates, such as polymers or nanostructures. Initially, flakes of monolayer MoS 2 were produced from natural MoS 2 crystals using micromechanical exfoliation, a topdown method capable of producing high-quality monolayers, albeit with poor throughput as well as limited control over flake thickness and dimensions. [4,30,31] Liquid-phase exfoliation of bulk crystals, on the other hand, offers good scalability, but often suffers from limited flake size, poor crystallinity, or contamination. [4,31,32] Bottom-up methods offer a more controllable way to produce MoS 2 films. High-quality MoS 2 thin films are most commonly deposited by chemical vapor deposition (CVD) or sulfurization of metal or metal oxide thin films. The most common Molybdenum disulfide (MoS 2 ) is a semiconducting 2D material, which has evoked wide interest due to its unique properties. However, the lack of controlled and scalable methods for the production of MoS 2 films at low temperatures remains a major hindrance on its way to applications. In this work, atomic layer deposition (ALD) is used to deposit crystalline MoS 2 thin films at a relatively low temperature of 300 °C. A new molybdenum precursor, Mo(thd) 3 (thd = 2,2,6,6-tetramethylheptane-3,5-dionato), is synthesized, characterized, and used for film deposition with H 2 S as the sulfur precursor. Self-limiting growth with a low growth rate of ≈0.025 Å cycle −1 , straightforward thickness control, and large-area uni...

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High Luminescence Efficiency in MoS₂ Grown by Chemical Vapor Deposition

Abstract: The user has requested enhancement of the downloaded file.

Cited by 156 publications

References 41 publications

Stacking-controllable interlayer coupling and symmetric configuration of multilayered MoS2

Stacking-controllable interlayer coupling and symmetric configuration of multilayered MoS2

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Atomic Layer Deposition of Crystalline MoS₂ Thin Films: New Molybdenum Precursor for Low‐Temperature Film Growth

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High Luminescence Efficiency in MoS2 Grown by Chemical Vapor Deposition

Abstract: The user has requested enhancement of the downloaded file.

Cited by 156 publications

References 41 publications

Stacking-controllable interlayer coupling and symmetric configuration of multilayered MoS2

Stacking-controllable interlayer coupling and symmetric configuration of multilayered MoS2

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Atomic Layer Deposition of Crystalline MoS2 Thin Films: New Molybdenum Precursor for Low‐Temperature Film Growth

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High Luminescence Efficiency in MoS₂ Grown by Chemical Vapor Deposition

Atomic Layer Deposition of Crystalline MoS₂ Thin Films: New Molybdenum Precursor for Low‐Temperature Film Growth