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Dupuch M, Kaemmel J, Alogna A, Reiter K, Cesarovic N, Stössel V, Ostach P, Falk V, Starck C, Hierold C. Inflow Cannula Pressure Sensor for Autonomous Dynamic Ventricular Assist Device Control. Thorac Cardiovasc Surg 2022. [DOI: 10.1055/s-0042-1742840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - J. Kaemmel
- German Heart Center Berlin, Berlin, Deutschland
| | - A. Alogna
- Medizinische Klinik m. S. Kardiologie Charité, Berlin, Deutschland
| | - K. Reiter
- Forschungseinrichtungen für Experimentelle Medizin (FEM), Charité-Universitätsmedizin Berlin, Berlin, Deutschland
| | - N. Cesarovic
- German Heart Institute Berlin, Berlin, Deutschland
| | - V. Stössel
- Forschungseinrichtungen für Experimentelle Medizin (FEM), Charité-Universitätsmedizin Berlin, Berlin, Deutschland
| | - P. Ostach
- Forschungseinrichtungen für Experimentelle Medizin (FEM), Charité-Universitätsmedizin Berlin, Berlin, Deutschland
| | - V. Falk
- Department of Cardiovascular Surgery, Charité – Universitätsmedizin Berlin, Berlin, Deutschland
| | - C. Starck
- German Heart Center Berlin, Berlin, Deutschland
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Boutry C, Müller M, Hierold C. Junctions between metals and blends of conducting and biodegradable polymers (PLLA-PPy and PCL-PPy). Materials Science and Engineering: C 2012; 32:1610-20. [DOI: 10.1016/j.msec.2012.04.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 12/01/2011] [Accepted: 04/22/2012] [Indexed: 12/01/2022]
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Schwyter ES, Helbling T, Glatz W, Hierold C. Fully automated measurement setup for non-destructive characterization of thermoelectric materials near room temperature. Rev Sci Instrum 2012; 83:074904. [PMID: 22852715 DOI: 10.1063/1.4737880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A measurement setup is presented that allows for a complete and non-destructive material characterization of electrochemically deposited thermoelectric material. All electrical (Seebeck coefficient α, electrical conductivity σ), thermal (thermal conductivity λ), and thermoelectric (figure of merit ZT) material parameters are determined within a single measurement run. The setup is capable of characterizing individual electrochemically deposited Bi(2+x)Te(3-x) pillars of various size and thickness down to a few 10 μm, embedded in a polymer matrix with a maximum measurement area of 1 × 1 cm(2). The temperature range is limited to an application specific window near room temperature of 10 °C to 70 °C. A maximum thermal flux of 1 W/cm(2) can be applied to the device under test (DUT) by the Peltier element driven heat source and sink. The setup has a highly symmetric design and DUTs can be mounted and dismounted within few seconds. A novel in situ recalibration method for a simple, quick and more accurate calibration of all sensors has been developed. Thermal losses within the setup are analysed and are mathematically considered for each measurement. All random and systematic errors are encountered for by a MATLAB routine, calculating all the target parameters and their uncertainties. The setup provides a measurement accuracy of ±2.34 μV/K for α, ±810.16 S/m for σ, ±0.13 W/mK for λ, and ±0.0075 for ZT at a mean temperature of 42.5 °C for the specifically designed test samples with a pillar diameter of 696 μm and thickness of 134 μm, embedded in a polyethylene terephthalate polymer matrix.
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Affiliation(s)
- E S Schwyter
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
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Peters C, Fusco S, Li Y, Kühne S, Nelson B, Hierold C. Backside Liquid Phase Photolithography for Fabricating Self-Organizing Hydrogel Bilayers. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.proeng.2012.09.372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Boutry C, Chandrahalim H, Hierold C. Characterization of RF Resonators Made of Biodegradable Materials for Biosensing Applications. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.proeng.2011.12.378] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Muoth M, Helbling T, Durrer L, Lee SW, Roman C, Hierold C. Hysteresis-free operation of suspended carbon nanotube transistors. Nat Nanotechnol 2010; 5:589-92. [PMID: 20601944 DOI: 10.1038/nnano.2010.129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 05/21/2010] [Indexed: 05/08/2023]
Abstract
Single-walled carbon nanotubes offer high sensitivity and very low power consumption when used as field-effect transistors in nanosensors. Suspending nanotubes between pairs of contacts, rather than attaching them to a surface, has many advantages in chemical, optical or displacement sensing applications, as well as for resonant electromechanical systems. Suspended nanotubes can be integrated into devices after nanotube growth, but contamination caused by the accompanying additional process steps can change device properties. Ultraclean suspended nanotubes can also be grown between existing device contacts, but high growth temperatures limit the choice of metals that can be used as contacts. Moreover, when operated in ambient conditions, devices fabricated by either the post- or pre-growth approach typically exhibit gate hysteresis, which makes device behaviour less reproducible. Here, we report the operation of nanotube transistors in a humid atmosphere without hysteresis. Suspended, individual and ultraclean nanotubes are grown directly between unmetallized device contacts, onto which palladium is then evaporated through self-aligned on-chip shadow masks. This yields pairs of needle-shaped source/drain contacts that have been theoretically shown to allow high nanotube-gate coupling and low gate voltages. This process paves the way for creating ultrasensitive nanosensors based on pristine suspended nanotubes.
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Affiliation(s)
- M Muoth
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
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Mattmann M, Roman C, Helbling T, Bechstein D, Durrer L, Pohle R, Fleischer M, Hierold C. Pulsed gate sweep strategies for hysteresis reduction in carbon nanotube transistors for low concentration NO(2) gas detection. Nanotechnology 2010; 21:185501. [PMID: 20388980 DOI: 10.1088/0957-4484/21/18/185501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Carbon-nanotube-based field effect transistors (CNFETs) have been employed as highly sensitive chemical sensors. Often used as the sensor output signal, the gate threshold voltage (V(th)) is subject to concentration-dependent shifts upon exposure to target analytes. However, an unambiguous determination of the intrinsic V(th) is usually hampered by substantial hysteresis in CNFET gate characteristics. In this study we show that short gate voltage (V(gd)) pulses can be used for hysteresis reduction in CNFETs as chemical sensors, in particular for NO(2) detection. In the pulsed operation regime, even small shifts of V(th) upon sub-ppm NO(2) exposure remain resolvable. Furthermore, the hysteretic behaviour is systematically investigated by varying the pulse waveforms and timing parameters. Finally, we use an adapted hysteresis model for pulsed V(gd) and employ it to discuss the measurement data.
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Affiliation(s)
- M Mattmann
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland.
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Helbling T, Hierold C, Roman C, Durrer L, Mattmann M, Bright VM. Long term investigations of carbon nanotube transistors encapsulated by atomic-layer-deposited Al(2)O(3) for sensor applications. Nanotechnology 2009; 20:434010. [PMID: 19801765 DOI: 10.1088/0957-4484/20/43/434010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Single-walled carbon nanotube field-effect transistors (CNFETs) are promising functional structures in future micro- or nanoelectronic systems and sensor applications. Research on the fundamental device concepts includes the investigation of the conditions for stable long term CNFET operation. CNFET operation in ambient air leads to on-state current degradation and fluctuating signals due to the well-known sensitivity of the electronic properties of the CNT to many environmental condition changes. It is the goal of device and sensor research to understand various kinds of sensor-environment interactions and to overcome the environmental sensitivity. Here, we show that the encapsulation of CNFETs by a thermal atomic-layer-deposited (ALD) aluminium oxide (Al(2)O(3)) layer of approximately 100 nm leads to stable device operation for 260 days and reduces their sensitivity to the environment. The characteristics of CNFETs prior to and after Al(2)O(3) encapsulation are comparatively investigated. It is found that encapsulation improves the stability of the CNFET characteristics with respect to the gate threshold voltage, hysteresis width and the on-state current, while 1/f noise is lowered by up to a factor of 7. Finally, CNFETs embedded in a dielectric membrane are employed as pressure sensors to demonstrate sensor operation of CNFETs encapsulated by ALD as piezoresistive transducers.
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Affiliation(s)
- T Helbling
- Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
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Muoth M, Gramm F, Asaka K, Durrer L, Helbling T, Roman C, Lee SW, Hierold C. Tilted-view transmission electron microscopy-access for chirality assignment to carbon nanotubes integrated in MEMS. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.proche.2009.07.150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Stampfer C, Güttinger J, Roman C, Jungen A, Helbling T, Hierold C. Electron shuttle instability for nano electromechanical mass sensing. Nano Lett 2007; 7:2747-52. [PMID: 17718586 DOI: 10.1021/nl0712419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We discuss the potential use of the electromechanical shuttle instability in suspended nanostructures (e.g., nanotubes or nanowires) for nanomechanical sensing. The tunneling-assisted (shuttle-like) electron transport mechanism is addressed from a mechanical and electromechanical point of view, showing strong dependencies on the fundamental frequency, the mechanical restoring and damping force, and the electromechanical charging of the suspended nanostructure. We propose to use these nonlinear dependencies to sense minute mass (and tension) changes. Therefore, we introduce a conceptual sensing device and investigate its operation in the frame of a simple model system. Finally, we discuss different measurement techniques and report on high sensitivities (e.g., 1 nA/zeptogram (zg), or 1 mV/zg depending on the measurement technique) and potential resolutions in the range of 10 zg (10(-23) kg).
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Affiliation(s)
- C Stampfer
- Micro and Nanosystems, ETH Zurich, 8092 Zurich, Switzerland.
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Jungen A, Stampfer C, Durrer L, Helbling T, Hierold C. Amorphous carbon contamination monitoring and process optimization for single-walled carbon nanotube integration. Nanotechnology 2007; 18:075603. [PMID: 21730505 DOI: 10.1088/0957-4484/18/7/075603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We detail the monitoring of amorphous carbon deposition during thermal chemical vapour deposition of carbon nanotubes and propose a contamination-less process to integrate high-quality single-walled carbon nanotubes into micro-electromechanical systems. The amorphous content is evaluated by confocal micro-Raman spectroscopy and by scanning/transmission electron microscopy. We show how properly chosen process parameters can lead to successful integration of single-walled nanotubes, enabling nano-electromechanical system synthesis.
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Affiliation(s)
- A Jungen
- Micro and Nanosystems, ETH Zurich, 8092 Zurich, Switzerland
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Graf D, Molitor F, Ensslin K, Stampfer C, Jungen A, Hierold C, Wirtz L. Spatially resolved Raman spectroscopy of single- and few-layer graphene. Nano Lett 2007; 7:238-42. [PMID: 17297984 DOI: 10.1021/nl061702a] [Citation(s) in RCA: 966] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We present Raman spectroscopy measurements on single- and few-layer graphene flakes. By using a scanning confocal approach, we collect spectral data with spatial resolution, which allows us to directly compare Raman images with scanning force micrographs. Single-layer graphene can be distinguished from double- and few-layer by the width of the D' line: the single peak for single-layer graphene splits into different peaks for the double-layer. These findings are explained using the double-resonant Raman model based on ab initio calculations of the electronic structure and of the phonon dispersion. We investigate the D line intensity and find no defects within the flake. A finite D line response originating from the edges can be attributed either to defects or to the breakdown of translational symmetry.
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Affiliation(s)
- D Graf
- Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland.
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Stampfer C, Jungen A, Linderman R, Obergfell D, Roth S, Hierold C. Nano-electromechanical displacement sensing based on single-walled carbon nanotubes. Nano Lett 2006; 6:1449-53. [PMID: 16834427 DOI: 10.1021/nl0606527] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present a nano-electromechanical system based on an individual single-walled carbon nanotube (SWNT) demonstrating their potential use for future displacement sensing at the nanoscale. The fabrication and characterization of the proposed nanoscaled transducer, consisting of a suspended metal cantilever mounted on top of the center of a suspended SWNT, is presented and discussed. The displacement of the nanoscale cantilever is detected via the electromechanically induced change in conductance of the strained SWNT. A relative differential resistance sensitivity (for a metallic SWNT) of up to 27.5%/nm was measured and a piezoresistive gauge factor of a SWNT of up to 2900 was extracted.
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Affiliation(s)
- C Stampfer
- Micro and Nanosystems, ETH Zurich, Switzerland.
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Stampfer C, Helbling T, Obergfell D, Schöberle B, Tripp MK, Jungen A, Roth S, Bright VM, Hierold C. Fabrication of single-walled carbon-nanotube-based pressure sensors. Nano Lett 2006; 6:233-7. [PMID: 16464041 DOI: 10.1021/nl052171d] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We report on the fabrication and characterization of bulk micromachined pressure sensors based on individual single-walled carbon nanotubes (SWNTs) as the active electromechanical transducer elements. The electromechanical sensor device consists of an individual electrically connected SWNT adsorbed on top of a 100-nm-thick atomic layer deposited (ALD) circular alumina (Al(2)O(3)) membrane with a radius in the range of 50-100 microm. A white light interferometer (WLI) was used to measure the deflection of the membrane due to differential pressure, and the mechanical properties of the device were characterized by bulge testing. Finally, we performed the first electromechanical measurements on strained metallic SWNTs adhering to a membrane and found a piezoresistive gauge factor of approximately 210 for metallic SWNTs.
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Affiliation(s)
- C Stampfer
- Micro and Nanosystems, ETH Zurich, 8092 Zurich, Switzerland.
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