Fabrication of ZnO Nanorods on MEMS Piezoresistive Silicon Microcantilevers for Environmental Monitoring

Xu, Jiushuai; Bertke, Maik; Gad, Alaaeldin; Feng, Yuqing; Hamdana, Gerry; Bakin, A.; Peiner, Erwin

doi:10.3390/proceedings1040290

Cited by 19 publications

(13 citation statements)

References 8 publications

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“…The deposition was carried out in a temperature-controlled chemical reactor, which was additionally equipped with a thermometer and a reflux condenser, for 3 h at 90 °C. After the reaction, the sample was cleaned with acetone and deionized water, successively [4]. Figure 2 shows the top-view SEM graphs with a tilt angle of 30° of the ZnO NRs grown on the ZnO seed-layers annealed at different temperatures, all the NRs were grown in the chemical bath at 90 °C for 3 h. As it can be seen from the graphs, the obtained ZnO NRs were vertically oriented with respect to the substrates, the NRs based on the seed-layers annealed at 600 °C (NRs-600) tends to have the best orientation.…”

Section: Area-selective Growth Of Aligned Zno Nanorods Arraysmentioning

confidence: 99%

Area-Selective Growth of Aligned ZnO Nanorod Arrays for MEMS Device Applications

Strempel

Zhou

et al. 2018

Eurosensors 2018

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ZnO nanorods (NRs) arrays with good vertical alignment were selectively grown on microscale patterned surfaces by a MEMS-compatible, low-temperature chemical-bath deposition method (CBD). The direct-current (DC) sputtered and subsequently annealed ZnO seed-layer was found to have a crucial effect on the ZnO NRs growth. Depending on the pre-annealing temperature between 200 °C and 700 °C, which is compatible with our microcantilever fabrication process, diameters and area densities of the NRs of 60–99 nm and 17–27 µm−2 were observed, respectively, with the best alignment at 600 °C. A surface-area enlargement factor of 48 was achieved with respect to a ZnO layer indicating the potential of ZnO NRs arrays for MEMS applications, such as gas sensing.

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Section: Area-selective Growth Of Aligned Zno Nanorods Arraysmentioning

confidence: 99%

Area-Selective Growth of Aligned ZnO Nanorod Arrays for MEMS Device Applications

Strempel

Zhou

et al. 2018

Eurosensors 2018

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“…The cantilever beam has a total length of 1000 µm, a width of 170 µm, and a thickness of 12 µm. Details of the fabrication procedure of the electro-thermal piezoresistive cantilever sensors covered by ZnO NRs and chitosan layer were described previously in [2,21,22]. Mechanical actuation is obtained by applying an alternating current (AC) voltage Vaccos(2πft) superimposed on a direct current (DC) voltage Vdc to the HR (Figure 3, in black line).…”

Section: Self-actuating and Self-sensingmentioning

confidence: 99%

Real-Time Frequency Tracking of an Electro-Thermal Piezoresistive Cantilever Resonator with ZnO Nanorods for Chemical Sensing

Setiono

Fahrbach

et al. 2019

Chemosensors

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The asymmetric resonance response in electro-thermal piezoresistive cantilever resonators causes a need of an optimization treatment for taking parasitic actuation-sensing effects into account. An electronic reference circuit for signal subtraction, integrated with the cantilever resonator has the capability to reduce the effect of parasitic coupling. Measurement results demonstrated that a symmetric amplitude shape (Lorentzian) and an optimized phase characteristic (i.e., monotonically decreasing) were successfully extracted from an asymmetric resonance response. With the monotonic phase response, real-time frequency tracking can be easier to implement using a phase-locked loop (PLL) system. In this work, an electro-thermal piezoresistive cantilever resonator functionalized with self-assembled monolayers of chitosan-covered ZnO nanorod arrays as sensitive layers has been investigated under different relative humidity (rH) levels. Enhancement of resonance phase response has been demonstrated by implementing the reference signal subtraction. Subsequently, a lock-in amplifier integrated with PLL system (MFLI, Zurich Instruments, Zurich, Switzerland) was then employed for continuously tracking the resonant frequency. As a result, we find a good correlation of frequency shift (∆f0) with change in rH monitored using a commercial reference sensor.

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“…However, the small active area of these sensors limits their sensitivity. In order to improve the sensitivity, the cantilever surface can be nanostructured with TiO 2 nanotubes or nanorods [17,18], ZnO nanorods or nanotubes [19][20][21], carbon nanotubes [22,23], mesoporous silica [24,25]. The surface can also be nanostructured with nanowires arrays [26,27].…”

Section: Introductionmentioning

confidence: 99%

Detection of Organophosphorous Chemical Agents with CuO-Nanorod-Modified Microcantilevers

Schlur

Agostini

Thomas

et al. 2020

Sensors

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Microcantilevers are really promising sensitive sensors despite their small surface. In order to increase this surface and consequently their sensitivity, we nanostructured them with copper oxide (CuO) nanorods. The synthesis of the nanostructure consists of the oxidation of a copper layer deposited beforehand on the surface of the sample. The oxidation is performed in an alkaline solution containing a mixture of Na(OH) and (NH4)2S2O8. The synthesis procedure was first optimized on a silicon wafer, then transferred to optical cantilever-based sensors. This transfer requires specific synthesis modifications in order to cover all the cantilever with nanorods. A masking procedure was specially developed and the copper layer deposition was also optimized. These nanostructured cantilevers were engineered in order to detect vapors of organophosphorous chemical warfare agents (CWA). The nanostructured microcantilevers were exposed to various concentration of dimethyl methylphosphonate (DMMP) which is a well-known simulant of sarin (GB). The detection measurements showed that copper oxide is able to detect DMMP via hydrogen interactions. The results showed also that the increase of the microcantilever surface with the nanostructures improves the sensors efficiency. The evolution of the detection performances of the CuO nanostructured cantilevers with the DMMP concentration was also evaluated.

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Fabrication of ZnO Nanorods on MEMS Piezoresistive Silicon Microcantilevers for Environmental Monitoring

Cited by 19 publications

References 8 publications

Area-Selective Growth of Aligned ZnO Nanorod Arrays for MEMS Device Applications

Area-Selective Growth of Aligned ZnO Nanorod Arrays for MEMS Device Applications

Real-Time Frequency Tracking of an Electro-Thermal Piezoresistive Cantilever Resonator with ZnO Nanorods for Chemical Sensing

Detection of Organophosphorous Chemical Agents with CuO-Nanorod-Modified Microcantilevers

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