Single Ion Adsorption and Switching in Nano-Electronics

TL;DR

This paper reports the first observation of single ion adsorption on carbon nanotubes, causing significant resistance changes, and highlights the importance of atomic-scale effects in future nano-electronic devices.

Contribution

It introduces the first detection of single gaseous ion interaction with microelectronic devices, revealing discrete resistance changes in CNTs due to single ion adsorption.

Findings

Single ion adsorption causes over two orders of magnitude resistance increase.

Only positive ions induce changes via ion potential induced carrier depletion.

Atomic scale effects become crucial as electronics scale down to one-dimensional structures.

Abstract

Single ion detection has, for many years, been the domain of large devices such as the Geiger counter, and studies on interactions of ionized gasses with materials have been limited to large systems. To date, there have been no reports on single gaseous ion interaction with microelectronic devices, and single neutral atom detection techniques have shown only small, barely detectable responses. Here, we report the first observation of single ion adsorption onto individual carbon nanotubes (CNTs), which, due to the severely restricted one-dimensional current path, experience discrete, quantized resistance increases of over two orders of magnitude. Only positive ions cause changes, by the mechanism of ion potential induced carrier depletion, which is supported by density functional and Landauer transport theory. Our observations reveal a new single-ion/CNT heterostructure with novel electronic properties, and demonstrate that as electronics are ultimately scaled towards the one-dimensional limit, atomic scale effects become increasingly important.