Carrier polarity engineering in carbon nanotube field-effect transistors by induced charges in polymer insulator

Shinya Aikawa, Sungjin Kim, Theerapol Thurakitseree, Erik Einarsson, Taiki Inoue, Shohei Chiashi, Kazuhito Tsukagoshi, Shigeo Maruyama

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4 Citations (Scopus)

Abstract

We present that the electrical conduction type in carbon nanotube field-effect transistors (CNT-FETs) can be converted by induced charges in a polyvinyl alcohol (PVA) insulator. When the CNT channels are covered with pure PVA, the FET characteristics clearly change from unipolar p-type to ambipolar. The addition of ammonium ions (NH4+) in the PVA leads to further conversion to unipolar n-type conduction. The capacitance - voltage characteristics indicate that a high density of positive charges is induced at the PVA/SiO2 interface and within the bulk PVA. Electrons are electrostatically accumulated in the CNT channels due to the presence of the positive charges, and thus, stable n-type conduction of PVA-coated CNT-FETs is observed, even under ambient conditions. The mechanism for conversion of the conduction type is considered to be electrostatic doping due to the large amount of positive charges in the PVA. A blue-shift of the Raman G-band peak was observed for CNTs coated with NH4+-doped PVA, which corresponds to unipolar n-type CNT-FET behavior. These results confirm that carrier polarity engineering in CNT-FETs can be achieved with a charged PVA passivation layer.

Original languageEnglish
Article number013501
JournalApplied Physics Letters
Volume112
Issue number1
DOIs
Publication statusPublished - 2018 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Aikawa, S., Kim, S., Thurakitseree, T., Einarsson, E., Inoue, T., Chiashi, S., Tsukagoshi, K., & Maruyama, S. (2018). Carrier polarity engineering in carbon nanotube field-effect transistors by induced charges in polymer insulator. Applied Physics Letters, 112(1), [013501]. https://doi.org/10.1063/1.4994114