The hot pick-up technique for batch assembly of van der Waals heterostructures

Pizzocchero, Filippo; Gammelgaard, Lene; Jessen, Bjarke S.; Caridad, José M.; Wang, Lei; Hone, James; Bøggild, Peter; Booth, Tim

doi:10.1038/ncomms11894

Cited by 560 publications

(588 citation statements)

References 34 publications

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“…Exfoliated or grown flakes can be precisely positioned on a substrate using several transfer methods for van der Waals assembly [11,13] e.g. by colamination [18,99,100] , PDMS stamping [101] or by a pick and place method [102,103] . The various stacking methods also allow the preparation of vertically stacked van der Waals heterostructures with precise control over the individual layers as well as the rotational alignment [104] .…”

Section: Fabricationmentioning

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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Section: Fabricationmentioning

confidence: 99%

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Wurstbauer¹,

Miller²,

Parzinger³

et al. 2017

J. Phys. D: Appl. Phys.

110

View full text Add to dashboard Cite

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“…Subsequent work showing a similar order-ofmagnitude improvement in more mechanically robust samples of graphene encapsulated in hexagonal boron nitride (hBN) supported by SiO 2 substrates is now the basis for routine production of high-performance graphene devices [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Suppression of intrinsic roughness in encapsulated graphene

et al. 2017

Self Cite

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Roughness in graphene is known to contribute to scattering effects which lower carrier mobility. Encapsulating graphene in hexagonal boron nitride (hBN) leads to a significant reduction in roughness and has become the de facto standard method for producing high-quality graphene devices. We have fabricated graphene samples encapsulated by hBN that are suspended over apertures in a substrate and used noncontact electron diffraction measurements in a transmission electron microscope to measure the roughness of encapsulated graphene inside such structures. We furthermore compare the roughness of these samples to suspended bare graphene and suspended graphene on hBN. The suspended heterostructures display a root mean square (rms) roughness down to 12 pm, considerably less than that previously reported for both suspended graphene and graphene on any substrate and identical within experimental error to the rms vibrational amplitudes of carbon atoms in bulk graphite. Our first-principles calculations of the phonon bands in graphene/hBN heterostructures show that the flexural acoustic phonon mode is localized predominantly in the hBN layer. Consequently, the flexural displacement of the atoms in the graphene layer is strongly suppressed when it is supported by hBN, and this effect increases when graphene is fully encapsulated.

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“…[11][12][13][14][15][16][17] The reason for its difficult exfoliation to a monolayer thickness is unclear, possibly being its AA′ stacking, its slightly-ionic bonds or flatness that causes adhesion between h-BN layers and other surfaces stronger than other 2D materials. [18][19][20][21] Moreover, h-BN surfaces are hydrophillic in nature, but after being exposed to air they get covered by an hydrophobic layer of hydrocarbons as reported in h-BN nanotubes 22 and graphene. 23 Understanding the adhesion, friction and other properties of single-layer h-BN can pave the way to promising applications, such as deep ultraviolet single photon emitters, 24,25 ultrathin piezotronics, 26,27 and to exploit its natural hyperbolic optical dispersion properties, 28 and proton conduction.…”

Section: Introductionmentioning

confidence: 99%

Mechanical characterization and cleaning of CVD single-layer h-BN resonators

et al. 2017

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Hexagonal boron nitride is a 2D material whose single-layer allotrope has not been intensively studied despite being the substrate for graphene electronics. Its transparency and stronger interlayer adhesion with respect to graphene makes it difficult to work with, and few applications have been proposed. We have developed a transfer technique for this extra-adhesive material that does not require its visual localization, and fabricated mechanical resonators made out of chemical vapor-deposited single-layer hexagonal boron nitride. The suspended material was initially contaminated with polymer residues from the transfer, and the devices showed an unexpected tensioning when cooling them to 3 K. After cleaning in harsh environments with air at 450°C and ozone, the temperature dependence changed with f 0 Q products reaching 2 × 10 10 Hz at room temperature. This work paves the way to the realization of highly sensitive mechanical systems based on hexagonal boron nitride, which could be used as an alternative material to SiN for optomechanics experiments at room temperature.

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The hot pick-up technique for batch assembly of van der Waals heterostructures

Cited by 560 publications

References 34 publications

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Suppression of intrinsic roughness in encapsulated graphene

Mechanical characterization and cleaning of CVD single-layer h-BN resonators

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