Enhanced Tunneling in a Hybrid of Single-Walled Carbon Nanotubes and Graphene

TY - JOUR

T1 - Enhanced Tunneling in a Hybrid of Single-Walled Carbon Nanotubes and Graphene

AU - Liao, Yongping

AU - Mustonen, Kimmo

AU - Tulic, Semir

AU - Skakalova, Viera

AU - Khan, Sabbir A.

AU - Laiho, Patrik

AU - Zhang, Qiang

AU - Li, Changfeng

AU - Monazam, Mohammad R. A.

AU - Kotakoski, Jani

AU - Lipsanen, Harri

AU - Kauppinen, Esko I.

N1 - [Qdev]

PY - 2019/10/22

Y1 - 2019/10/22

N2 - Transparent and conductive films (TCFs) are of great technological importance. Their high transmittance, electrical conductivity, and mechanical strength make single-walled carbon nanotubes (SWCNTs) a good candidate for the raw material for TCFs. Despite the ballistic transport in individual SWCNTs, electrical conductivity of SWCNT networks is limited by low efficiency of charge tunneling between the tube elements. Here, we demonstrate that the nanotube network sheet resistance at high optical transmittance is decreased by more than 50% when fabricated on graphene. This is a comparable improvement as that obtained through gold chloride (AuCl3) doping. However, while Raman spectroscopy reveals substantial changes in spectral features of AuCl3 doped nanotubes, this does not occur with graphene. Instead, temperature-dependent transport measurements indicate that a graphene substrate reduces the tunneling barrier heights, while its parallel conductivity contribution is almost negligible. Finally, we show that combining the graphene substrate and AuCl3 doping, brings the SWCNT thin film sheet resistance down to 36 ω/â-i.

AB - Transparent and conductive films (TCFs) are of great technological importance. Their high transmittance, electrical conductivity, and mechanical strength make single-walled carbon nanotubes (SWCNTs) a good candidate for the raw material for TCFs. Despite the ballistic transport in individual SWCNTs, electrical conductivity of SWCNT networks is limited by low efficiency of charge tunneling between the tube elements. Here, we demonstrate that the nanotube network sheet resistance at high optical transmittance is decreased by more than 50% when fabricated on graphene. This is a comparable improvement as that obtained through gold chloride (AuCl3) doping. However, while Raman spectroscopy reveals substantial changes in spectral features of AuCl3 doped nanotubes, this does not occur with graphene. Instead, temperature-dependent transport measurements indicate that a graphene substrate reduces the tunneling barrier heights, while its parallel conductivity contribution is almost negligible. Finally, we show that combining the graphene substrate and AuCl3 doping, brings the SWCNT thin film sheet resistance down to 36 ω/â-i.

KW - SWCNT

KW - graphene

KW - transport

KW - conductivity

KW - transparent and conductive films

U2 - 10.1021/acsnano.9b05049

DO - 10.1021/acsnano.9b05049

M3 - Journal article

C2 - 31497949

SN - 1936-0851

VL - 13

SP - 11522

EP - 11529

JO - ACS Nano

JF - ACS Nano

IS - 10

ER -