Fabrication and Characterization of MWCNT-Based Bridge Devices

Abstract

Abstract-Carbon nanotubes (CNTs) are one of the most actively researched structural materials due to their interesting electrical, mechanical, and chemical properties. Unlike single walled carbon nanotubes (SWCNTs), little work has been focused on multi-walled carbon nanotubes (MWCNTs) and their potential for practical devices. Here, we have fabricated bridgeshape devices integrating MWCNTs (> 50 nm in outer diameter) using three processes: optical lithography, electron beam-induced platinum deposition, and surface micromachining. Each device consists of a doubly-clamped nanotube suspended over gold electrodes on a highly conductive Si substrate. The suspended nanotubes are characterized individually using Raman spectroscopy and semiconductor parameters analysis and, overall, show, high crystallinity and low electrical resistance. The spring constants of doubly-clamped nanotubes were characterized using atomic force microscopy force−displacement measurements, with values as high as 70 N/m observed. Highly stiff MWCNTs are promising for a variety of applications, such as resonators and electrical interconnects. Through simulations, we estimate the resonance frequencies and pull-in voltages of these suspended nano-structures. The dependence of key parameters, such as the nanotube's length, Young's modulus, axial stress, and wall thickness is also discussed.

The quest for highly sensitive QCM humidity sensors: The coating of CNT/MOF composite sensing films as case study

“…The base solution of HKUST-1 was synthesized in accord with previously reported method [52][53][54][55]. to 11 µm in length [56]. In addition to that, 1 mg of CNT was dispersed in 2.5 g of isopropanol to form the plain CNT mixtures, which we use as a reference.…”

Miniature pressure sensor based on suspended MWCNT

“…Thus, CNTs have been used as an additive to improve the transduction properties of sensing films [9,10,12]. On the other hand, CNTs were explored in few studies as standalone sensing elements, mainly as bridge resonators [15,17].…”

“…The overall steps used for fabricating the devices are shown in Fig. 1, and detailed in [17]. In summary, Plasma-enhanced chemical vapor deposition (PECVD) was used for depositing 500 nm of amorphous Si (used as the sacrificial material) on Si wafer with 1 µm thick thermally grown SiO2.…”

Performance analysis of mixed CNT bundle interconnects at 10 nm technology

“…Particularly, it provides an extraordinary and unique thermal conductivity as high as 5800 W/m‐K, higher current carrying ability of 10 14 A/m 2 , and longer mean free path (MFP) in the range of micrometre [3]. As per the fabrication house [4, 5], a single‐walled CNT (SWCNT) possesses the following pros and cons as compared to multi‐walled CNT (MWCNT): (i) requires catalyst during synthesis; (ii) bulk synthesis is difficult due to the requirement of suitable atmospheric conditions and appropriate growth; (3) probability of defect during functionality is significantly higher; and (4) separation of metallic and semiconductor CNT is challenging task [6, 7]. These conclude that the reliability of SWCNT is lesser compared to an MWCNT interconnects during a grown process.…”

“…The effective resistance of MCB is approximately three times lower than SWCNT and MWCNT due to the higher packing density of MCB [8]. Additionally, the MCBs demonstrates several advantages such as (i) lower contact resistance; (ii) negligible impact of inter‐CNT coupling capacitance; and (iii) straight forward fabrication process and potential benefit of improving the conduction channels [4, 8, 9]. Furthermore, the nature of growing the CNTs inside a bundle is purely random and follows the Gaussian distribution depending on the process control and synthesis condition.…”