Characterization and selective deposition of carbon nanotubes from carbon nanoparticles mixture using mild acid treatment and electrokinetic manipulation

Abstract

Particle manipulation is often required in the fabrication of microelectronic devices such as transistors and sensors. In this work, we succeeded in depositing aligned carbon nanotubes (CNTs) from an oxidized conglomerates carbon mixture using a simple low power procedure consisting of mild acid treatment and frequency-dependent dielectrophoretic (DEP) force. The treatment improved the dispersity and solubility of CNTs due to the functional groups introduced on their surface. The DEP force was generated with an AC signal of 1 MHz and 7.07 Vrms to attract the CNTs to a transparent electrode gap of 50 μm. Treatment quality was confirmed and characterized by Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), energy dispersive x-ray analysis (EDX) and high-resolution transmission electron microscopy (HRTEM). Ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) were used to analyze the dispersity and solubility of carbon particles and their size distribution in different solvents. The morphology of the deposited CNTs and amorphous carbon were observed by optical microscope and field-emission scanning electron microscope (FESEM). The procedure used in this work is cost-effective, scalable and essential for future assembly. Furthermore, the transparency of the system makes it suitable for real-time observation, transparent sensors, and the ability to integrate it into microfluidic channels.

Airflow-assisted dielectrophoresis to reduce the resistance mismatch in carbon nanotube-based temperature sensors

“…The fourth sample was a mixture of MWCNTs and conductive amorphous carbon (CAC) functionalized with nitric acid, as described elsewhere. 40 One mg of each sample was added to 20 mL of dimethylformamide (DMF) at different concentrations. The solutions were sonicated for 30 minutes in a cold bath to form MWCNT suspensions.…”

Dielectrophoretic alignment of carbon nanotubes: theory, applications, and future

“…Among the listed, the latter treatment is preferred since it is widely available, cost-effective, and requires much simpler installation. As the name implies, the wet chemical treatment utilizes wet chemicals, such as HCL [45], HNO 3 [46], H 2 O 2 [47], H 2 SO 4 [48], or a mixture of two or more acids to functionalize the tubes [49][50][51]. The harshness of the treatment is determined by several factors, including acid concentration, sonication time, treatment temperature, and oxidizing agents.…”

Carbon Nanotube Alignment Methods

“…Several million devices were packaged in a square centimeter [61]. Recent studies concluded that the quality of aligned CNTs using DEP depends on many factors, such as the electrode design [62,63], suspension quality [64], and CNTs enrichment [65,66].…”