Design and performance of a microcantilever-based hydrogen sensor

Baselt, David R.; Frühberger, Bernd; Klaassen, E.H.; Cemalovic, Sabina; Britton, C.L.; Patel, Sanjay V.; Mlsna, Todd; McCorkle, D.L.; Warmack, Bruce

doi:10.1016/s0925-4005(02)00315-5

Cited by 207 publications

(118 citation statements)

References 15 publications

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“…Because it is flammable between concentrations of 4% and 75% in air, safety sensors for leak detection are required. In recent years, a variety of sensor concepts has emerged such as resistivitybased [1,2], MOS-based [3,4], optical [5], cantilever-based [6] or nanogap-based sensors [7,8]. Most of these devices make use of palladium (Pd) as the sensitive material because of its highly catalytic surface and a large solubility of atomic hydrogen [9,10].…”

Section: Introductionmentioning

confidence: 99%

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

et al. 2010

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Fast hydrogen sensors based on discontinuous palladium (Pd) films on supporting polyimide layers, fabricated by a cost-efficient and full-wafer compatible process, are presented. The films, deposited by electron-beam evaporation with a nominal thickness of 1.5 nm, consist of isolated Pd islands that are separated by nanoscopic gaps. On hydrogenation, the volume expansion of Pd brings initially separated islands into contact which leads to the creation of new electrical pathways through the film. The supporting polyimide layer provides both sufficient elasticity for the Pd nanoclusters to expand on hydrogenation and a sufficiently high surface energy for good adhesion of both film and contacting electrodes. The novel order of the fabrication processes involves a dicing step prior to the Pd deposition and stencil lithography for the patterning of microelectrodes. This allows us to preserve the as-deposited film properties. The devices work at room temperature, show response times of a few seconds and have a low power consumption of some tens of nW.

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Section: Introductionmentioning

confidence: 99%

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

et al. 2010

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“…This property makes a Pd film an effective functional layer for optical hydrogen detection 3,31,33 . Pd-coated cantilevers were previously studied as capacitive hydrogen sensors [34][35][36] . In addition to changes in reflectivity, stress induced by hydrogen-induced lattice expansion (HILE) causes the cantilever to deform.…”

Section: Introductionmentioning

confidence: 99%

Realization of palladium-based optomechanical cantilever hydrogen sensor

McKeown

Wang

et al. 2017

Microsyst Nanoeng

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Hydrogen has attracted attention as an alternative fuel source and as an energy storage medium. However, the flammability of hydrogen at low concentrations makes it a safety concern. Thus, gas concentration measurements are a vital safety issue. Here we present the experimental realization of a palladium thin film cantilever optomechanical hydrogen gas sensor. We measured the instantaneous shape of the cantilever to nanometer-level accuracy using diffraction phase microscopy. Thus, we were able to quantify changes in the curvature of the cantilever as a function of hydrogen concentration and observed that the sensor's minimum detection limit was well below the 250 p.p.m. limit of our test equipment. Using the change in curvature versus the hydrogen curve for calibration, we accurately determined the hydrogen concentrations for a random sequence of exposures. In addition, we calculated the change in film stress as a function of hydrogen concentration and observed a greater sensitivity at lower concentrations.Keywords: hydrogen detection; imaging and sensing; interference microscopy; optomechanics; optical sensors; surface dynamics INTRODUCTIONHydrogen has always been viewed as a promising alternative to fossil fuels, and it can also function as an effective energy storage medium for intermittent energy sources. In addition, hydrogen is used in a range of other industries, including chemical production, metal refining, and food processing. A major safety concern with hydrogen is combustibility. Therefore, early leak detection and concentration determination of hydrogen have been areas of intense research 1-3 . There are various types of hydrogen sensors that use a wide range of detection mechanisms. Lundström et al. 4 proposed metal oxide semiconductor (MOS)-type hydrogen sensors 5 . However, MOS sensors suffer from drawbacks such as premature saturation of detectable hydrogen concentrations and low sensitivity. Other MOS-based devices have been used as hydrogen sensors, such as MOS field-effect transistors (FETs) 6,7 , high electron mobility transistors [8][9][10] , and Schottky diode-type FETs 11,12 . However, these devices require complicated fabrication processes and have high production costs. Optical gas sensors 13-21 not only overcome these disadvantages but also have other unique advantages, such as negligible electrical interference, no risk of ignition from an electrical spark, and the ability to work at high temperatures or in harsh environments.Palladium (Pd) can absorb up to 900 times its own weight in hydrogen gas at room temperature 22 . Compared with platinum 23 , Pd film is more popular because of its lower cost. Pd alloys with Ag, Au, Ni, and WO 3 have also been studied 24-29 because of their improved response time 24,25,27 , sensitivity 28,29 , and durability 26 as a sensing material. The alloys can avoid blistering effects 26 and the α to β phase transition at higher hydrogen concentrations 25,27 .

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“…Both read out principles have a large potential, the static mode is most often used (as in this thesis) for its relative simplicity. Reported cantilever read out methods are on the basis of changes in capacitance [43,44,54], changes in the piezoresistivity [49,50,55], and optical beam deflection detected with a position sensitive detector, see for example reference [52,56]. These methods have a typical deflection resolution of at best ~1 pm.…”

Section: Cantilever-based Gas Sensorsmentioning

confidence: 99%

“…Microcantilever-based sensors, which have effectively been exploited for biological, chemical, and gas sensing applications, can be operated in either dynamic mode by monitoring the resonant frequency of the cantilever (CL), or static mode by measuring its stress-induced deflection, as the target binds to the functionalized surface of the CL [14,[132][133][134][135][136][137]. The deflection of the CL can be determined by means of bulky deflection of an optical beam [56] or electrical, i.e., capacitive, piezoresistive, or piezoelectric read-outs [43,54,55]. Alternatively, fully integrated optical read-out with a CL waveguide was firstly presented in 2006 by Zinoviev et al [138] and in the following three years by other groups [139][140][141][142].…”

Section: Introductionmentioning

confidence: 99%

“…At room temperature and atmospheric pressure, palladium can absorb up to 900 times its own volume of hydrogen [143]. Absorption of H2 by Pd causes the CL, suspended above the GWG, to curl down [43,54,56], which narrows the GWG-CL gap, g, and leads to a stronger interaction between the CL and the GWG evanescent modal field, which results in a red-shift of the transmission spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Integrated optical sensor utilizing slow-light propagation in grated-waveguide cavities

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Design and performance of a microcantilever-based hydrogen sensor

Cited by 207 publications

References 15 publications

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

Realization of palladium-based optomechanical cantilever hydrogen sensor

Integrated optical sensor utilizing slow-light propagation in grated-waveguide cavities

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