Constraints and Challenges in Tip-Based Nanofabrication

Tseng, Ampere A.

doi:10.1007/978-1-4419-9899-6_12

Cited by 4 publications

(5 citation statements)

References 106 publications

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“…Adsorbates can sometimes be mechanically manipulated by AFM 19 , raising the possibility of patterning friction on these materials. For monolayer graphene on SiO 2 , scanning at the low normal force used for imaging (1 nN) often minimally affects the frictional domains, but scanning at high normal force (30 nN) reproducibly reorients the domains ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…This nanotexture strongly resembles patterns of adsorbates observed on graphite 16 17 18 and we induce an apparently identical nanotexture on flakes of hexagonal boron nitride (hBN) using a thermal cycling procedure. Consistent with the adsorbate picture, we can rapidly and predictably reorient the frictional domains by scanning a probe tip along the flake in a chosen direction—a departure from nanoassembly techniques 19 such as dip-pen nanolithography 20 and nanografting 21 , for which writing a different ‘colour' requires submerging the sample in a different ‘ink'.…”

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confidence: 85%

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Switchable friction enabled by nanoscale self-assembly on graphene

et al. 2016

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Graphene monolayers are known to display domains of anisotropic friction with twofold symmetry and anisotropy exceeding 200%. This anisotropy has been thought to originate from periodic nanoscale ripples in the graphene sheet, which enhance puckering around a sliding asperity to a degree determined by the sliding direction. Here we demonstrate that these frictional domains derive not from structural features in the graphene but from self-assembly of environmental adsorbates into a highly regular superlattice of stripes with period 4–6 nm. The stripes and resulting frictional domains appear on monolayer and multilayer graphene on a variety of substrates, as well as on exfoliated flakes of hexagonal boron nitride. We show that the stripe-superlattices can be reproducibly and reversibly manipulated with submicrometre precision using a scanning probe microscope, allowing us to create arbitrary arrangements of frictional domains within a single flake. Our results suggest a revised understanding of the anisotropic friction observed on graphene and bulk graphite in terms of adsorbates.

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Section: Resultsmentioning

confidence: 99%

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confidence: 85%

Switchable friction enabled by nanoscale self-assembly on graphene

et al. 2016

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“…Therefore, the feasibility of especially extreme shallow inverted 2DEGs is even more difficult. In contrast, MODFETs were synthesized with channel depth down to 34 nm [41,42]. Despite such circumstances, the inverted interface benefits from the absence of AlGaAs as well as of the DX-centers in doped-AlGaAs at the surface-facing side with respect to hybrid systems.…”

Section: Shallow Inverted Algaas/gaas Heterostructuresmentioning

confidence: 99%

The improved inverted AlGaAs/GaAs interface: its relevance for high-mobility quantum wells and hybrid systems

Külah

Reichl

Scharnetzky

et al. 2021

Semicond. Sci. Technol.

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Two dimensional electron gases (2DEGs) realized at GaAs/AlGaAs single interfaces by molecular-beam epitaxy (MBE) reach mobilities of about 15 million cm2 V s−1 if the AlGaAs alloy is grown after the GaAs. Surprisingly, the mobilities may drop to a few millions for the identical but inverted AlGaAs/GaAs interface, i.e. reversed layering. Here we report on a series of inverted heterostructures with varying growth parameters including temperature, doping, and composition. Minimizing the segregation of both dopants and background impurities leads to mobilities of 13 million cm2 V s−1 for inverted structures. The dependence of the mobility on electron density tuned by a gate or by illumination is found to be the identical if no doping layers exist between the 2DEG and the respective gate. Otherwise, it differs significantly compared to normal interface structures. Reducing the distance of the 2DEG to the surface down to 50 nm requires an additional doping layer between 2DEG and surface in order to compensate for the surface-Schottky barrier. The suitability of such shallow inverted structures for future semiconductor-superconductor hybrid systems is discussed. Lastly, our understanding of the improved inverted interface enables us to produce optimized double-sided doped quantum wells exhibiting an electron mobility of 40 million cm2 V s−1 at 1 K.

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“…'The size accuracy or dimension variation is critical since the ability to fabricate a specific structure with a specific dimension dictates the use of the unique dimension-dependent properties in nanodevices. The size control capability is absent in many existing TBN methods' [15]. In the laser-based methods, piezoscanners (extended by stepper motors) or mirror scanners are also applied.…”

Section: Deficits and Limitsmentioning

confidence: 99%

Towards alternative 3D nanofabrication in macroscopic working volumes

Kühnel

Fröhlich

Füßl

et al. 2018

Meas. Sci. Technol.

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This paper gives an overview of the research carried out at TU Ilmenau towards the development and application of tip- and laser-based nanofabrication on flat and curved surfaces in extended macroscopic working areas. It is shown that sub-10 nm structures can be fabricated by scanning probe lithography (SPL). The use of soft stamps has revealed their suitability for nanoimprinting on curved surfaces. Laser-based methods for a maskless exposure of resist on curved surfaces utilising 405 nm laser diodes have already been tested successfully. Furthermore, the current work deals with two-photon polymerisation, which has great potential with regard to the fabrication of sub-wavelength structures. At present, the methods mentioned have all been applied only in working ranges <100 × 100 μm2 in the plane and <10 μm in height. To overcome these limitations, the nanofabrication techniques are now being integrated in the nanopositioning and measuring machines (NPMMs) developed at TU Ilmenau. They offer working volumes of up to 200 × 200 × 25 mm3 with a positioning resolution of 20 pm. To provide access to any geometry elements in the 3D space with nanometre precision, the machine concepts as well as the metrological concepts are further developed. Due to the increased demands of lowest trajectory deviations within the fabrication process, new real-time controllers for probing and fabrication systems are investigated, as well as interactions in combined force and positioning sensors. Further important research is carried out into interference lithography, to enable an exposure of non-planar substrates and to improve the lateral structure resolution at the same time. A mix-and-match combination of such methods that allows the simultaneous exposure of large substrate regions with nanofabrication methods such as SPL becomes possible on the basis of the NPMMs, and is another area of great potential with regard to the research work presented in this paper.

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Constraints and Challenges in Tip-Based Nanofabrication

Cited by 4 publications

References 106 publications

Switchable friction enabled by nanoscale self-assembly on graphene

Switchable friction enabled by nanoscale self-assembly on graphene

The improved inverted AlGaAs/GaAs interface: its relevance for high-mobility quantum wells and hybrid systems

Towards alternative 3D nanofabrication in macroscopic working volumes

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