Carbon nanotube micro-contactors on ohmic substrates for on-chip microelectromechanical probing applications at wafer level

Tas, Mehmet O.; Baker, Mark; Musaramthota, Vishal; Uppal, Hasan; Masteghin, Mateus G.; Bentz, Jedidiah; Boxshall, Keir; Stolojan, Vlad

doi:10.1016/j.carbon.2019.04.115

Cited by 5 publications

(15 citation statements)

References 70 publications

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“…Whilst defects may have been introduced during the bending and stretching of the CNTs, it is also possible that the top of the CNT forest may have a higher intrinsic quality than the bulk of the CNT forest due to the way the growth process is terminated. 43 It should be noted here that, when the CNTs are grown on Si wafers, the rolling method does not work due to lack of adhesion between the Si substrate and the CNT film resulting in sections of the CNT films detaching from the substrate. The Al2O3 substrate is much rougher than a standard polished Si substrate (see supplementary information Figure S3 for the substrate roughness analysis), which could have provided the better adhesion between the CNT film and the substrate.…”

Section: Resultsmentioning

confidence: 99%

“…Electromechanical characterization of the composite films is carried out using a reconfigured setup described here, consisting of a high-precision, ultralow load, single-point load cell (Tedea-Huntleigh 0.3 kg with a load cell amplifier) attached to a motorized z-stage (Thorlabs 300 mm DC Servo Stage with TDC 001 controller, controlled via Kinesis software), a displacement laser (Keyence LK-G), and a source/measure unit (see Figure S2 for the experimental setup visualization). For tensile stress–strain tests, CNT-PDMS films are affixed between a base stage and a motorized stage via Cu clamps.…”

Section: Methodsmentioning

confidence: 99%

“…Electromechanical characterization of the composite films is carried out using a reconfigured setup described here 43…”

Section: Electromechanical Characterisationmentioning

confidence: 99%

“…62 The high durability of CNT-based sensors is probably due to the high elastic behavior of CNTs, preventing plastic deformation and fracture of CNTs under dynamic loading. 4,43 Figure 5 Under dynamic loading, such as would occur with skin-attachable and wearable applications, electrical hysteresis behaviour becomes important. Large hysteresis results in irreversible sensing performance when strain sensors are subjected to dynamic loading.…”

Section: Achieved This By Fragmentation Of Cnts On Pdms and Similarlymentioning

confidence: 99%

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Highly Stretchable, Directionally Oriented Carbon Nanotube/PDMS Conductive Films with Enhanced Sensitivity as Wearable Strain Sensors

Tas

Baker

Masteghin

et al. 2019

ACS Appl. Mater. Interfaces

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Recent interest in the fields of human motion monitoring, electronic skin and human-machine interface technology demand strain sensors with high stretchability/compressibility (ε > 50%), high sensitivity (or gauge factor (GF > 100) and long-lasting electromechanical compliance. However, current metal and semiconductor-based strain sensors have very low (ε < 5%) stretchability or low sensitivity (GF < 2), typically sacrificing the stretchability for high-sensitivity. Composite elastomer sensors are a solution where the challenge is to improve the sensitivity to GF > 100. We propose a simple, low cost fabrication of mechanically compliant, physically robust metallic carbon nanotube (CNT)-polydimethylsiloxane (PDMS) strain sensors. The process allows the alignment of CNTs within the PDMS elastomer, permitting directional sensing. Aligning CNTs horizontally (HA-CNTs) on the substrate before embedding in the PDMS reduces the number of CNT junctions and introduces scale-like features on the CNT film perpendicular to the tensile strain direction, resulting in improved sensitivity compared to vertically-aligned CNT-(VA-CNT)-PDMS strain sensors under tension. The CNT alignment and the scale-like features modulate the electron conduction pathway, affecting the electrical sensitivity. Resulting GF are 594 at 15 % and 65 at 50 % strains for HA-CNT-PDMS and 326 at 25 % and 52 at 50 % strains for VA-CNT-PDMS sensors. Under compression, VA-CNT-PDMS show more sensitivity to small-scale deformation than HA-CNT-PDMS due to the CNT orientation and the continuous morphology of the film, demonstrating that the sensing ability can be improved by aligning the CNTs in certain directions. Furthermore, mechanical robustness and electromechanical durability are tested for over 6000 cycles to up to 50 % tensile and compressive strains, with good frequency response with negligible hysteresis. Finally, both types of sensors are shown to detect small-scale human motions, successfully distinguishing various human motions with reaction and recovery times of as low as 130 ms and 0.5 s respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Electromechanical characterization of the composite films is carried out using a reconfigured setup described here 43…”

Section: Electromechanical Characterisationmentioning

confidence: 99%

Section: Achieved This By Fragmentation Of Cnts On Pdms and Similarlymentioning

confidence: 99%

See 2 more Smart Citations

Highly Stretchable, Directionally Oriented Carbon Nanotube/PDMS Conductive Films with Enhanced Sensitivity as Wearable Strain Sensors

Tas

Baker

Masteghin

et al. 2019

ACS Appl. Mater. Interfaces

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“…The PTCVD system was operated at around 400–420 °C substrate temperature, measured using a bulk pyrometer. 67 The Fe 0 catalyst was activated for 5 min under 100 sccm H 2 , immediately followed by 5 min growth under 100 sccm H 2 and 25 sccm (acetylene) C 2 H 2 at 5 torr chamber pressure. After 5 min, C 2 H 2 supply was cut-off, hydrogen (H 2 ) was allowed to flowing into the chamber with the optical light on for an extra minute to avoid amorphous carbon built-up on the tip of the CNTs.…”

Section: Methodsmentioning

confidence: 99%

An easy to assemble PDMS/CNTs/PANI flexible supercapacitor with high energy-to-power density

et al. 2022

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Direct Growth of Vertically Aligned Carbon Nanotubes onto Transparent Conductive Oxide Glass for Enhanced Charge Extraction in Perovskite Solar Cells

Ferguson

Tas

et al. 2020

Adv Materials Inter

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Vertically aligned carbon nanotubes (VACNTs) present an exciting avenue for nanoelectronics due to their predetermined orientation and exceptional transport capabilities along the tube length, with the potential to be employed in a variety of optoelectronic applications. However, growth of VACNTs using conventional chemical vapor deposition (CVD) methods requires elevated temperatures (>720 °C) and therefore, the suitability of commonly used transparent conductive oxide (TCO) glasses, such as fluorine‐doped tin oxide (FTO) and indium‐tin oxide (ITO), as the substrates for nanotube growth are limited by their temperature‐sensitive nature. Here, the successful growth of multi‐walled VACNTs directly onto commonly used TCO glasses, FTO and ITO, using the photo‐thermal chemical vapor deposition (PTCVD) growth method is reported. The benefit of reflection, within the infrared region, of the TCO substrate and the effect of surface roughness on the growth of VACNTs is investigated. The application of VACNTs on ITO in inverted planar perovskite solar cells is investigated, which shows superior charge transfer, larger grain sizes in the perovskite film, and a champion device efficiency approaching 16%.

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Carbon nanotube micro-contactors on ohmic substrates for on-chip microelectromechanical probing applications at wafer level

Cited by 5 publications

References 70 publications

Highly Stretchable, Directionally Oriented Carbon Nanotube/PDMS Conductive Films with Enhanced Sensitivity as Wearable Strain Sensors

Highly Stretchable, Directionally Oriented Carbon Nanotube/PDMS Conductive Films with Enhanced Sensitivity as Wearable Strain Sensors

An easy to assemble PDMS/CNTs/PANI flexible supercapacitor with high energy-to-power density

Direct Growth of Vertically Aligned Carbon Nanotubes onto Transparent Conductive Oxide Glass for Enhanced Charge Extraction in Perovskite Solar Cells

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