Marek E. Schmidt

Metal-free plasma-enhanced chemical vapor deposition of large area nanocrystalline graphene

This paper reports on large area, metal-free deposition of nanocrystalline graphene (NCG) directly onto wet thermally oxidized 150 mm silicon substrates using parallel-plate plasma-enhanced chemical vapor deposition. Thickness non-uniformities as low as 13% are achieved over the whole substrate. The cluster size of the as-obtained films is determined from Raman spectra and lies between 1.74 and 2.67 nm. The film uniformity was further confirmed by Raman mapping. The sheet resistance of 3.73 and charge carrier mobility μ of are measured. We show that the NCG films can be readily patterned by reactive ion etching. NCG is also successfully deposited onto quartz and sapphire substrates and showed % optical transparency in the visible light spectrum.

Interaction study of nitrogen ion beam with silicon

Focused ion beam technology with light gas ions has recently gained attention with the commercial helium and neon ion beam systems. These ions are atomic, and thus, the beam/sample interaction is well understood. In the case of the nitrogen ion beam, several questions remain due to the molecular nature of the source gas, and in particular, if and when the molecular bond is split. Here, the authors report a cross-sectional scanning transmission electron microscopy (STEM) study of irradiated single crystalline silicon by various doses and energies of nitrogen ionized in a gas field ion source. The shape and dimensions of the subsurface damage is compared to Monte Carlo simulations and show very good agreement with atomic nitrogen with half the initial energy. Thus, it is shown that the nitrogen molecule is ionized as such and splits upon impact and proceeds as two independent atoms with half of the total beam energy. This observation is substantiated by molecular dynamics calculations. High resolution STEM ...

Controlled fabrication of electrically contacted carbon nanoscrolls

Carbon nanoscrolls (CNS) with their open ended morphology have recently attracted interest due to the potential application in gas capture, biosensors and interconnects. However, CNS currently suffer from the same issue that have hindered widespread integration of CNTs in sensors and devices: formation is done ex situ, and the tubes have to be placed with precision and reliability-a difficult task with low yield. Here, we demonstrate controlled in situ formation of electrically contacted CNS from suspended graphene nanoribbons with slight tensile stress. Formation probability depends on the length to width aspect ratio. Van der Waals interaction between the overlapping layers fixes the nanoscroll once formed. The stability of these CNSs is investigated by helium nano ion beam assisted in situ cutting. The loose stubs remain rolled and mostly suspended unless subject to a moderate helium dose corresponding to a damage rate of 4%-20%. One CNS stub remaining perfectly straight even after touching the SiO2 substrate allows estimation of the bending moment due to van der Waals force between the CNS and the substrate. The bending moment of 5400 eV is comparable to previous theoretical studies. The cut CNSs show long-term stability when not touching the substrate.

Nitrogen Gas Field Ion Source (GFIS) Focused Ion Beam (FIB) Secondary Electron Imaging: A First Look

The recent technological advance of the gas field ion source (GFIS) and its successful integration into systems has renewed the interest in the focused ion beam (FIB) technology. Due to the atomically small source size and the use of light ions, the limitations of the liquid metal ion source are solved as device dimensions are pushed further towards the single-digit nanometer size. Helium and neon ions are the most widely used, but a large portfolio of available ion species is desirable, to allow a wide range of applications. Among argon and hydrogen,

Structurally Controlled Large-Area 10 nm Pitch Graphene Nanomesh by Focused Helium Ion Beam Milling

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Influence of surface processing on the fracture strength of structurally integrated PZT fibers in shaped sheet metal parts

ions offer unique characteristics due to their covalent bond and their use as dopant for various carbon-based materials including diamond. Here, we provide a first look at the

Sub 0.5 V bias voltage operation of a triple-topgate graphene tunnel field effect transistor

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