A Simple Chemical Route To Selectively Eliminate Metallic Carbon Nanotubes in Nanotube Network Devices

Abstract

Semiconducting-only single-walled carbon nanotube (SWNT) network field effect transistors (FETs) have been fabricated by selectively reacting all the metallic SWNTs in the devices with diazonium reagents in a controlled manner. We have shown that the concentration of diazonium reagents used is crucial for selectively eliminating metallic SWNTs and keeping semiconducting ones intact. Excessive amounts of diazonium reagents can indiscriminately react with both metallic and semiconducting SWNTs and thus degrade the performance of the devices. This new technique will facilitate the process of fabrication of high-performance SWNT-based electronic devices.

Parallel arrays of individually addressable single-walled carbon nanotube field-effect transistors

“…19,31 Although the presence of a small percentage of metallic tubes is evident based on three terminal measurements, the high-current response mainly results from multiple ͑parallel͒ channels in the device. 32 The output ͑I ds vs V ds ͒ and the transfer ͑I ds vs V g ͒ characteristics of a typical, purely sc device ͑gap 60͒ are shown in Fig.…”

“…The remaining devices with varying degrees of metallic contributions can be easily converted to purely sc transistors by electric-field treatment. [16][17][18][19] The transconductance of the as-fabricated devices surpasses the current p-MOSFETs and can be further improved by a suitable treatment to remove metallic tubes in the channel. These desirable device properties offer a wide range of technological applications of the fabricated devices.…”

“…15 Despite these demonstrated breakthroughs, the progress toward CNT-based electronics has been rather slow due to a lack of ͑a͒ technique͑s͒ to produce pure, isolated semiconducting SWNTs and ͑b͒ a process for an industrially scalable production of useful devices. Since most growth techniques yield a mixture of metallic ͑m͒ and semiconducting ͑sc͒ SWNTs, which are often difficult to separate, ingenious methods such as high electric-fieldinduced destruction 16,17 and chemically modified deactivation 18,19 of m SWNTs have been proposed and utilized to realize sc SWNT devices.…”

Type- and Species-Selective Air Etching of Single-Walled Carbon Nanotubes Tracked with in Situ Raman Spectroscopy

“…Another possibility is that metallic species are more sensitive to defects formed during growth, resulting in greater reactivity. 83,84 Mechanisms of selectivity related to the electronic density of states near the Fermi level for m-CNTs are also often used to explain enhanced metallic etch rate. 22,38,85 For example, An et al have attributed the selective reactivity of diazonium reagents with m-CNTs to the stabilization of a charge-transfer complex formed at the metallic density of states.…”

Selective Separation of Single-Walled Carbon Nanotubes in Solution

“…Hence, s-SWCNTs are widely investigated due to the pursued applications in field-emission transistors (FETs). 9,11,15 To maximize the performance of FETs, it is desirable to obtain SWCNTs with similar diameter, chirality and thus band-gaps, and connect them in parallel to build each FET device for sufficient on-currents and reproducible device characteristics. The lengths of SWCNTs should also be controllable to meet the requirement of desired channel length.…”