Wafer‐Scale Fabrication of Suspended Single‐Walled Carbon Nanotube Arrays by Silver Liquid Dynamics

Abstract

Suspended single-walled carbon nanotubes (SWNTs) have advantages in mechanical resonators and highly sensitive sensors. Large-scale fabrication of suspended SWNTs array devices and uniformity among SWNTs devices remain a great challenge. This study demonstrates an effective, fast, and wafer-scale technique to fabricate suspended SWNT arrays, which is based on a dynamic motion of silver liquid to suspend and align the SWNTs between the prefabricated palladium electrodes in high temperature annealing treatment. Suspended, strained, and aligned SWNTs are synthesized on a 2 × 2 cm substrate with an average density of 10 tubes per micrometer. Under the optimal conditions, almost all SWNTs become suspended. A promising formation model of suspended SWNTs is established. The Kelvin four-terminal resistance measurement shows that these SWNT array devices have extreme low contact resistance. Meanwhile, the suspended SWNT array field effect transistors are fabricated by selective etching of metallic SWNTs using electrical breakdown. This method of large-scale fabrication of suspended architectures pushes the study of nanoscale materials into a new stage related to the electrical physics and industrial applications.

Large positive magnetoresistance in semiconducting single-walled carbon nanotubes at room temperature

“…19,20 Post-synthetic approaches have also been used such as current-induced electrical breakdown, which was proven to be effective owing to the high selectivity and complete removal of metallic SWNTs. 16,[21][22][23] Herein, we further investigate the change in MR behaviour as we gradually remove metallic SWNTs by electrical breakdown. Fig.…”

Room‐Temperature Carbon Nanotube Single‐Electron Transistors with Mechanical Buckling–Defined Quantum Dots

“…The fabrication method of suspended and strained SWNT devices was demonstrated in the recent work . The first step was to make a pair of palladium electrodes (thickness: 100 nm) on SiO 2 (800 nm)/Si substrate using electron‐beam lithography (Vistec EBPG 5000plus ES, Germany).…”

“…Then, the devices with suspended and strained SWNTs were fabricated successfully. In the recent work, the optimal channel length was shown around 1 µm when fabricated suspended SWNT devices . As the channel length increased, there would be some small silver particles in the middle part of the channel.…”

“…The size of the silver particles was statistically measured as shown in the histogram (Figure S1c, Supporting Information) and the average diameter was 87 nm. Another important condition was that the SWNTs in the devices were strained which had been simulated in the recent work . This strain in the SWNT was the key factor in terms of bending the nanotube at the connection between the SWNT and silver particle to form two buckles.…”

Observation of Van Hove Singularities and Temperature Dependence of Electrical Characteristics in Suspended Carbon Nanotube Schottky Barrier Transistors

“…The Schottky barrier transistors were fabricated by a technique that we reported recently [ 16 ], which used the dynamic motion of silver liquid to suspend the SWNTs between prefabricated palladium electrodes during high-temperature annealing. First, a small quantity of SWNTs with a density of approximately a single SWNT per 5 µm was deposited onto the silver film, under which there were patterned palladium electrodes.…”