Modeling of graphene Hall effect sensors for microbead detection

Manzin, A.; Simonetto, Enrico; Amato, Giampiero; Panchal, Vishal; Kazakova, Olga

doi:10.1063/1.4917323

Cited by 8 publications

(13 citation statements)

References 20 publications

(35 reference statements)

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“…Graphene sensors were patterned into a Greek-cross-shaped structure, which is established as the classical structure for effective Hall sensors with the lowest offset voltage. The sensing area of the sensors is the central area between the arms of the cross shape . The sensors were laid out in a horizontal array across each channel to eliminate the need for flow-focusing structures, and flow channels were fabricated over the sensors.…”

Section: Resultsmentioning

confidence: 99%

Prismatic Deflection of Live Tumor Cells and Cell Clusters

et al. 2018

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The analysis of heterogeneous subpopulations of circulating tumor cells (CTCs) is critical to enhance our understanding of cancer metastasis and enable non-invasive cancer diagnosis and monitoring. The phenotypic variability and plasticity of these cells – properties closely linked to their clinical behavior – demand techniques that isolate viable, discrete fractions of tumor cells for functional assays of their behavior and detailed analysis of biochemical properties. Here, we introduce the Prism Chip, a high-resolution immunomagnetic profiling and separation chip which harnesses a cobalt-based alloy to separate a flowing stream of nanoparticle-bound tumor cells with differential magnetic loading into ten discrete streams. Using this approach, we achieve exceptional purity (5.7 log white blood cell depletion) of isolated cells. We test the differential profiling function of the integrated device using prostate cancer blood samples from a mouse xenograft model. Using integrated graphene Hall sensors, we demonstrate concurrent automated profiling of single cells and CTC clusters that belong to distinct subpopulations based on protein surface expression.

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Section: Resultsmentioning

confidence: 99%

Prismatic Deflection of Live Tumor Cells and Cell Clusters

et al. 2018

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“…The voltage response of semiconductor Hall devices to the stray field of an ensemble of superparamagnetic nanobeads is simulated by means of a 2D finite element code, which enables to calculate the spatial distribution of the electric potential inside the Hall plate under the assumptions of diffusive transport regime and non-uniform magnetic field [8,20]. In the implemented model, the electron transport is described by means of a spatially dependent conductivity tensor   with elements…”

Section: Numerical Modelmentioning

confidence: 99%

“…The developed finite element model was proven to be reliable under different operative conditions, being already validated by comparison to experimental results in various applications of miniaturized Hall sensors. In particular, it was previously used in the detection of a single magnetic microbead [8] and in the calibration of magnetic tips via scanning gate microscopy technique [23,29].…”

Section: Numerical Modelmentioning

confidence: 99%

“…Additionally, they are generally characterized by a linear response, being not affected by magnetic saturation as magnetoresistive devices. These features make miniaturized Hall sensors suitable for the detection of magnetic nanobeads [4][5][6][7][8][9] used as labels for manipulating, monitoring and Manuscript received October 03, 2018. This work was supported by Project 15SIB06 NanoMag "Nano-scale traceable magnetic field measurements", a joint research project funded by the European Metrology Programme for Innovation and Research (EMPIR).…”

Section: Introductionmentioning

confidence: 99%

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Quantification of Magnetic Nanobeads With Micrometer Hall Sensors

2018

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This paper investigates the suitability of miniaturized semiconductor Hall devices for the quantification of magnetic nanobeads usable in biomedical applications. The analysis demonstrates the existence of conditions for which the Hall voltage signal is not proportional to bead number, focusing on the detection of a 2D array of superparamagnetic nanobeads, immobilized on the sensor surface. The study is performed by means of a numerical modeling procedure, which provides the spatial distribution of the electric potential inside the Hall plate, under the assumptions of diffusive electron transport regime and non-uniform magnetic field. We find that proportionality of the sensor response to bead number and possibility to use micro-Hall devices as magnetic bead counters are strongly affected by the magnetostatic dipolar interactions between beads. We also observe a deviation from linearity, due to the spatial nonuniformity in the device response, which is strongly influenced by the planar position of the beads with respect to the device active area. These aspects are investigated in detail by varying external field amplitude, device dimension, bead number, interbead distance, bead vertical position and size of the area occupied by beads. The parametric analysis is performed simulating an ac-dc Hall magnetometry technique.

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“…Graphene is a two-dimensional material with excellent electronic, thermal, and mechanical properties, which makes it a promising candidate not only for future applications in micro- and nanoelectronics but also for nanoelectromechanical systems. − Recent work has focused on the application of graphene as a Hall sensor element because of its high charge carrier mobility. − It is well understood that the interaction of the graphene layer with the substrate limits the charge carrier mobility because of doping effects and surface roughness. ,− It is therefore advantageous to use freestanding graphene membranes, which eliminates the influence of the substrate. Graphene membranes have also been used as piezoresistive and capacitive pressure sensors , and condenser microphones with graphene as a diaphragm. − For the latter, one can expect first resonances in the megahertz range due to graphene’s ultimate thinness, with potential for several hundred gigahertz resonance frequencies for membranes with nanoscale diameters .…”

Section: Introductionmentioning

confidence: 99%

Graphene Membranes for Hall Sensors and Microphones Integrated with CMOS-Compatible Processes

Wittmann

Glacer

Wagner

et al. 2019

ACS Appl. Nano Mater.

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Graphene is a promising candidate for future electronic devices because of its outstanding electronic and mechanical properties. The high charge carrier mobility in graphene, particularly in substrate-free suspended form, suggests applications as Hall effect sensors. In addition, graphene membranes are highly desirable as pressure sensors or microphones. Here, suitable integration processes for freestanding graphene devices with standard CMOS processes are demonstrated. We propose a process flow for graphene membrane-based Hall sensors and microphones that is CMOS back end of the line compatible. The Hall sensors show mobilities up to 11900 cm2 V–1 s–1, which are higher than in germanium- and GaAs-based Hall sensors. Graphene-based microphones are resonance-free for frequencies up to 700 kHz, i.e., in the acoustic wave region, which is a unique advantage over conventional microelectromechanical (MEMS) microphones.

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Modeling of graphene Hall effect sensors for microbead detection

Cited by 8 publications

References 20 publications

Prismatic Deflection of Live Tumor Cells and Cell Clusters

Prismatic Deflection of Live Tumor Cells and Cell Clusters

Quantification of Magnetic Nanobeads With Micrometer Hall Sensors

Graphene Membranes for Hall Sensors and Microphones Integrated with CMOS-Compatible Processes

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