Irek E. Rosłoń, Robin J. Dolleman, Hugo Licona, Martin Lee, Makars Šiškins, Henning Lebius, Lukas Madauß, Marika Schleberger, Farbod Alijani, Herre S. J. van de… 展开作者
Irek E. Rosłoń, Robin J. Dolleman, Hugo Licona, Martin Lee, Makars Šiškins, Henning Lebius, Lukas Madauß, Marika Schleberger, Farbod Alijani, Herre S. J. van der Zant, Peter G. Steeneken
Porous, atomically thin graphene membranes have interesting properties for filtration and sieving applications because they can accommodate small pore sizes, while maintaining high permeability. These membranes are therefore receiving much attention for novel gas and water purification applications. Here we show that the atomic thickness and high resonance frequency of porous graphene membranes enables an effusion based gas sensing method that distinguishes gases based on their molecular mass. Graphene membranes are used to pump gases through nanopores using optothermal forces. By monitoring the time delay between the actuation force and the membrane mechanical motion, the permeation time-constants of various gases are shown to be significantly different. The measured linear relation between the effusion time constant and the square root of the molecular mass provides a method for sensing gases based on their molecular mass. The presented microscopic effusion based gas sensor can provide a small, low-power alternative for large, high-power, mass-spectrometry and optical spectrometry based gas sensing methods.
The micro-electromechanical-system (MEMS) force and acceleration sensor utilizing the graphene-induced non-radiative transition was investigated. The graphene-induced non-radiative transition is very sensitive to the distance, and the deflection of the graphene ribbon is highly susceptive to applied force or acceleration. Thus, a high-sensitivity MEMS sensor can be achieved with detecting the graphene ribbon's deflection of 1 nm, the force of 0.1 pN, and the acceleration of 0.1 mg. The MEMS sensor, with a size of only tens of microns, can be charged by light irradiation without connecting powe…
Hall sensors batch-fabricated on all-CVD h-BN/graphene/h-BN heterostructures
二维（2D）材料石墨烯由于其在室温下具有高载流子迁移率和低载流子浓度的潜力而非常有希望用于霍尔传感器。在这里，我们报告了使用市售的大面积CVD生长材料在六方氮化硼（h-BN）中封装的石墨烯上批量制造磁性霍尔传感器。采用层转移技术制备了全CVD生长的h-BN/graphene/h-BN van der Waals异质结构，并批量制备了具有一维边缘金属接触的霍尔传感器。在室温下测量了高达97 V/AT的电流相关霍尔灵敏度。霍尔传感器在晶圆级上表现出稳健的性能，在周围环境中具有超过六个月的稳定特性。这项工作为全CVD 2D材料异质结构的生长和制造技术的进一步发展开辟了道路，并允许进一步改善霍尔传感器的实际应用性能。
Sensitive capacitive pressure sensors based on graphene membrane arrays
石墨烯膜的高柔性、不渗透性和强度是能够实现下一代纳米机械传感器的关键特性。然而，对于电容式压力传感器，由单个悬浮的石墨烯膜提供的灵敏度太小而不能与商业传感器竞争。在这里，我们实现了由近万个小型独立双层石墨烯膜阵列组成的高灵敏度电容式压力传感器。我们使用一种即使在高温退火后也能保持石墨烯优越的材料和机械性能的方法制造大阵列的小直径膜。这些传感器使用低成本电池供电的电路板读取，响应度高达47.8 aF Pa $^{-1}$ mm $^{-2}$，从而优于商业传感器。
What level of scientific knowledge has been gained against COVID-19 during the months of the pandemic? Are current technologies able to keep up with the advances in virology research? Historically, disease outbreaks due to pathogenic microorganisms have killed many more people than wars have, and the ability that viral genes have displayed to rapidly change and adapt has forced new studies. Early detection is most important for timely management of any biological attack, whether natural or intentional, and rapid detection systems are essential to counter the effects of viral disease. Optical s…
The infrared (IR) photoresponse of graphene synthesized by an atmospheric chemical vapor deposition (CVD) system using a mixture of hydrogen and methane gases was studied. The IR sensor devices were fabricated using graphene films transferred onto a SiO2 substrate by a lift-off process. The quality of graphene was investigated with Raman spectroscopy and optical microscopy. The photoresponse was recorded under the illumination of IR light of wavelength 850 nm and intensity of around 0.216 mW/cm^2. The effects of temperature and hydrogenation on photoconductivity were also studied. It was found…
All-electronic interrogation of biofluid flow velocity by sensors incorporated in ultra-low-power or self-sustained systems offers the promise of enabling multifarious emerging research and applications. Electrical sensors based on nanomaterials are of high spatiotemporal resolution and exceptional sensitivity to external flow stimulus and easily integrated and fabricated using scalable techniques. But existing nano-based electrical flow-sensing technologies remain lacking in precision and stability and are typically only applicable to simple aqueous solutions or liquid/gas dual-phase mixtures…
We propose a novel bio-sensor structure composed of slot dual-micro-ring resonators and mono-layer graphene.Based on the electromagnetically induced transparency (EIT)-like phenomenon and the light-absorption characteristics of graphene,we present a theoretical analysis of transmission by using the coupled mode theory and Kubo formula.The results demonstrate the EIT-like spectrum with asymmetric line profile.The mode-field distributions of transmission spectrum obtained from 3D simulations based on finite-difference time-domain (FDTD) method.Our bio-sensor exhibit theoretical sensitivity of 33…
Humidity sensing is important to a variety of technologies and industries, ranging from environmental and industrial monitoring to medical applications. Although humidity sensors abound, few available solutions are thin, transparent, compatible with large-area sensor production and flexible, and almost none are fast enough to perform human respiration monitoring through breath detection or real-time finger proximity monitoring via skin humidity sensing. This work describes chemiresistive graphene-based humidity sensors produced in few steps with facile liquid phase exfoliation (LPE) followed b…
Biomonitoring wearable sensors based on two-dimensional nanomaterials have lately elicited keen research interest and potential for a new range of flexible nanoelectronic devices. Practical nanomaterial-based devices suited for real-world service, which have first-rate performance while being an attractive accessory, are still distant. We report a multifunctional flexible wearable sensor fabricated using an ultra-thin percolative layer of microwave exfoliated graphene nanosheets on laser-patterned gold circular inter-digitated electrodes for monitoring vital human physiological parameters. Thi…
A novel ultra-sensitive Parity-Time symmetry based Graphene FET (PTS-GFET) sensor is studied for gas concentration detection. The PTS-GFET sensor effectively integrates the sensitivity of the PT symmetry around its Exceptional Point (EP) and the tunability of the GFET conductance. The change of GFET conductance with the gas concentration can be brought back to the EP of the PTS-GFET by tuning the gate voltage on the GFET. Thus, the applied gate voltage indicates the gas concentration. The minimum detectable gas concentration has been derived and estimated based on the experimental data, which …
Effect of YIG Nanoparticle Size and Clustering in Proximity-Induced Magnetism in Graphene/YIG Composite Probed with Magnetoimpedance Sensors: Towards Improved Functionality, Sensitivity and Proximity Detection
The human body is punctuated with wide array of sensory systems that provide a high evolutionary advantage by facilitating formation of a detailed picture of the immediate surroundings. The sensors range across a wide spectrum, acquiring input from non-contact audio-visual means to contact based input via pressure and temperature. The ambit of sensing can be extended further by imparting the body with increased non-contact sensing capability through the phenomenon of electrostatics. Here we present graphene-based tattoo sensor for proximity sensing, employing the principle of electrostatic gat…
Flexible pressure sensors are an attractive area of research due to their potential applications in biomedical sensing and wearable devices. Among flexible and wearable pressure sensors, capacitive pressure sensors show significant advantages, owing to their potential low cost, ultra-low power consumption, tolerance to temperature variations, high sensitivity, and low hysteresis. In this work, we develop capacitive flexible pressure sensors using graphene based conductive foams. In these soft and porous conductive foams, graphene is present either as a coating of the pores in the foam, inside …
This paper presents an electrolytically gated broadband microwave sensor where atomically-thin graphene layers are integrated into coplanar waveguides and coupled with microfluidic channels. The interaction between a solution under test and the graphene surface causes material and concentration-specific modifications of graphene's DC and AC conductivity. Moreover, wave propagation in the waveguide is modified by the dielectric properties of materials in its close proximity via the fringe field, resulting in a combined sensing mechanism leading to an enhanced S-parameter response compared to me…
This work reports the modeling and simulation of gas sensors made from pristine graphene nanoplatelets (P-GnPs) using COMSOL Multiphysics software. The mass balance equation was solved while including contributions of electromigration flux. An example GnP-based gas sensor was simulated to undergo exposure to NO2 and CO gases at different concentrations to understand the effects of adsorption. Various electrical properties and the overall sensor responses were also studied as a function of gas concentration in order to determine how viable such sensors could be for target gases. The results her…
Semi-permeable membranes are important elements in water purification and energy generation applications, for which the atomic thickness and strength of graphene can enhance efficiency and permeation rate while maintaining good selectivity. Here, we show that an osmotic pressure difference forms across a suspended graphene membrane as a response to a sucrose concentration difference, providing evidence for its semi-permeability. This osmotic pressure difference is detected via the deflection of the graphene membrane that is measured by atomic force microscopy. Using this technique, the time de…
