Molecular beam epitaxy growth of atomically ultrathin MoTe2 lateral heterophase homojunctions on graphene substrates

Yu, Yayun; Guang, Wang; Qin, Shiqiao; Wu, Nannan; Wang, Zhenyu; He, Ke; Zhang, Xueao

doi:10.1016/j.carbon.2017.01.026

Cited by 48 publications

(47 citation statements)

References 30 publications

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“…These are attributed to the MBE‐derived low T G window (<400 °C) and far from equilibrium condition (<10 −6 mbar) for 2H‐MoTe 2 growths. Similar random aligned MBE‐MoTe 2 nuclei were also observed on graphene epitaxial templates by different groups . Additional images grown at the intermediate processes are also shown for reference (Figure S7, Supporting Information).…”

supporting

confidence: 68%

“…Nevertheless, MoTe 2 is a strain‐sensitive phase change material . MBE‐derived MoTe 2 nanosheets have been grown on graphite, MoS 2 , sapphire, CaF 2 , graphene and InAs substrates, however, the preliminary 2D lateral growth and phase manipulation has rarely been successful . The large lattice mismatch of −5.44% between the superlattices of (4 × 4) MoTe 2 and (6 × 6) graphene appears to be detrimental for 2H‐phase formation due to strain‐induced 2H → 1Tʹ phase change .…”

mentioning

confidence: 99%

“…MBE‐derived MoTe 2 nanosheets have been grown on graphite, MoS 2 , sapphire, CaF 2 , graphene and InAs substrates, however, the preliminary 2D lateral growth and phase manipulation has rarely been successful . The large lattice mismatch of −5.44% between the superlattices of (4 × 4) MoTe 2 and (6 × 6) graphene appears to be detrimental for 2H‐phase formation due to strain‐induced 2H → 1Tʹ phase change . Notably, for practical applications, a tedious transfer process from metal catalysts or epitaxial templates to device compatible substrates (e.g., SiO 2 /Si) is inevitable, which adversely degrading the quality of TMDs .…”

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confidence: 99%

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Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe₂ on Inert Amorphous Dielectrics

et al. 2019

Advanced Materials

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Transition metal dichalcogenides (TMDs) (MX 2 , M = Mo or W, X = S, Se, or Te) have attracted intense interest for developing ultrascaled electronics and optoelectronics by virtue of their attractive 2D layered structures and unique physical properties that are absent in their bulk counterparts. [1][2][3][4][5] Monolayer semiconducting TMDs show sizable direct bandgaps, quantum confinement effects, large exciton binding energies and effective valley polarizations, which unveils widespread applications in field-effect transistors (FETs), photodetectors, light-emitting diodes, pumped lasers, solar cells, and valleytronic devices. [6][7][8][9][10] More excitingly, their 2D structures offer superior electrostatic controllability and exemptible short-channel effects, rendering TMDs promising candidates for future sub-10 nm complimentary metal-oxide-semiconductor (CMOS) devices. [5,11,12] The applications of exfoliated TMD flakes in building high-performance prototypes of electronics, photonics, and optoelectronics have already been demonstrated. [13][14][15][16] The exfoliated flakes, however, suffer from Monolayer MoTe 2 , with the narrowest direct bandgap of ≈1.1 eV among Mo-and W-based transition metal dichalcogenides, has attracted increasing attention as a promising candidate for applications in novel near-infrared electronics and optoelectronics. Realizing 2D lateral growth is an essential prerequisite for uniform thickness and property control over the large scale, while it is not successful yet. Here, layer-by-layer growth of 2 in. wafer-scale continuous monolayer 2H-MoTe 2 films on inert SiO 2 dielectrics by molecular beam epitaxy is reported. A single-step Mo-flux controlled nucleation and growth process is developed to suppress island growth. Atomically flat 2H-MoTe 2 with 100% monolayer coverage is successfully grown on inert 2 in. SiO 2 /Si wafer, which exhibits highly uniform in-plane structural continuity and excellent phonon-limited carrier transport behavior. The dynamics-controlled growth recipe is also extended to fabricate continuous monolayer 2H-MoTe 2 on atomic-layer-deposited Al 2 O 3 dielectric. With the breakthrough in growth of wafer-scale continuous 2H-MoTe 2 monolayers on device compatible dielectrics, batch fabrication of high-mobility monolayer 2H-MoTe 2 field-effect transistors and the three-level integration of vertically stacked monolayer 2H-MoTe 2 transistor arrays for 3D circuitry are successfully demonstrated. This work provides novel insights into the scalable synthesis of monolayer 2H-MoTe 2 films on universal substrates and paves the way for the ultimate miniaturization of electronics.

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confidence: 68%

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confidence: 99%

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confidence: 99%

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Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe₂ on Inert Amorphous Dielectrics

et al. 2019

Advanced Materials

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“…After mechanically exfoliation from the bulk crystals (see the Experimental Section), the MoTe 2 flakes are characterized with Raman spectroscopy. As shown in Figure a, the Raman spectrum of 1L to 5L MoTe 2 exhibits the characteristic peaks nearly located at ≈171, ≈234, and ≈289 cm −1 , corresponding to the three different vibration modes A 1g , E 1 2g , and A 2 1g in MoTe 2 crystal lattice, respectively . For the FET devices, metal electrodes (50 nm/2 nm Au/Ag) were evaporated onto the flakes with standard electrobeam lithography process (see the Experimental Section).…”

Section: Resultsmentioning

confidence: 99%

Carrier Modulation of Ambipolar Few‐Layer MoTe₂ Transistors by MgO Surface Charge Transfer Doping

Luo

Zhu

Peng

et al. 2017

Adv Funct Materials

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Semiconducting molybdenum ditelluride (2H-MoTe 2 ), a fast-emerging 2D material with an appropriate band gap and decent carrier mobility, is configured as field-effect transistors and is the focus of substantial research interest, showing hole-dominated ambipolar characteristics. Here, carrier modulation of ambipolar few-layer MoTe 2 transistors is demonstrated utilizing magnesium oxide (MgO) surface charge transfer doping. By carefully adjusting the thickness of MgO film and the number of MoTe 2 layers, the carrier polarity of MoTe 2 transistors from p-type to n-type can be reversely controlled. The electron mobility of MoTe 2 is significantly enhanced from 0.1 to 20 cm 2 V −1 s −1 after 37 nm MgO film doping, indicating a greatly improved electron transport. The effective carrier modulation enables to achieve high-performance complementary inverters with high DC gain of >25 and photodetectors based on few-layer MoTe 2 flakes. The results present an important advance toward the realization of electronic and optoelectronic devices based on 2D transition-metal dichalcogenide semiconductors.

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“…[28][29][30] Growing epitaxial thin films of MoTe 2 (and WTe 2 ) by MBE is challenging because Mo (W) and Te have very similar electronegativities [31] so during coevaporation of Mo (W) and Te, the material tends to form intermetallic MoMo or WW bonds which do not favor the incorporation of Te in the material resulting in poor Te-deficient and highly nonstoichiometric films. Following the successful growth of the stable 1T′-WTe 2 by MBE on a variety of 2D substrates by employing interrupted growth methodology, [31] a few works [32][33][34] have reported the stable 2H MoTe 2 phase by MBE but the metastable 1T′ MoTe 2 phase was elusive until recently when two independent groups [35,36] showed evidence of room temperature 1T′ MBE films mixed with 2H on epi-graphene/SiC substrates. [35] However, they lack of information about the epitaxial quality and the thin film structure; it is not known in particular whether they adopt the monoclinic (β-MoTe 2 ) or orthorhombic (γ-MoTe 2 ) structure.…”

Section: (2 Of 12)mentioning

confidence: 99%

Direct Observation at Room Temperature of the Orthorhombic Weyl Semimetal Phase in Thin Epitaxial MoTe₂

Tsipas

Fragkos

Tsoutsou

et al. 2018

Adv Funct Materials

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Molecular beam epitaxy growth of atomically ultrathin MoTe2 lateral heterophase homojunctions on graphene substrates

Cited by 48 publications

References 30 publications

Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe₂ on Inert Amorphous Dielectrics

Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe₂ on Inert Amorphous Dielectrics

Carrier Modulation of Ambipolar Few‐Layer MoTe₂ Transistors by MgO Surface Charge Transfer Doping

Direct Observation at Room Temperature of the Orthorhombic Weyl Semimetal Phase in Thin Epitaxial MoTe₂

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Molecular beam epitaxy growth of atomically ultrathin MoTe2 lateral heterophase homojunctions on graphene substrates

Cited by 48 publications

References 30 publications

Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe2 on Inert Amorphous Dielectrics

Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe2 on Inert Amorphous Dielectrics

Carrier Modulation of Ambipolar Few‐Layer MoTe2 Transistors by MgO Surface Charge Transfer Doping

Direct Observation at Room Temperature of the Orthorhombic Weyl Semimetal Phase in Thin Epitaxial MoTe2

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Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe₂ on Inert Amorphous Dielectrics

Molecular Beam Epitaxy Scalable Growth of Wafer‐Scale Continuous Semiconducting Monolayer MoTe₂ on Inert Amorphous Dielectrics

Carrier Modulation of Ambipolar Few‐Layer MoTe₂ Transistors by MgO Surface Charge Transfer Doping

Direct Observation at Room Temperature of the Orthorhombic Weyl Semimetal Phase in Thin Epitaxial MoTe₂