Semiconducting van der Waals Nanocarbon on Boron Nitride Nanotubes

The use of nanocarbon in future electronics is promising and has gained significant attention after the discovery of carbon nanotubes (CNTs) and graphene. The major obstacles are that not all single-walled CNTs are semiconducting as their properties are chiral-dependence, and graphene is metallic and not applicable for digital switching.<br/><br/>In contrast to CNTs and graphene, BNNTs are electrically insulating and optically transparent [1, 2]. The unique properties of BNNTs have enabled the formation of single-electron transistors (SETs) without semiconductors [3]. We have also demonstrated the formation of 2D gold with tunable optical band gaps [4], field-effect transistors (FETs) by Tellurium (Te) atomic chains inside BNNTs [5], and high-brightness fluorophores that could be 1000X brighter than existing dyes [6-8]. Here we will introduce a novel class of carbon electronic materials, nanocarbon functionalized BNNTs with semiconducting characteristics.<br/><br/>Van der Waals nanocarbon is selectively coated on BNNTs without using any catalyst. Raman spectroscopy, scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS) are used to analyze the structural properties of this nanocarbon. Four-probe scanning tunneling microscopy further characterized the as-grown nanocarbon on BNNTs for their electronic properties (4-probe STM). Non-linear current-voltage (I-V) characteristics are detected, suggesting that these carbon are not metallic. Furthermore, the transport properties of this nanocarbon are evaluated at various transport lengths ranging from 300 to 800 nm. Interestingly, the turn-on voltages of this nanocarbon drastically decreased with the decrease of the transport lengths. The details of the experimental results and the theoretical modeling will be discussed in the meeting.<br/><br/><b>References</b><br/>[1] J. Wang, <i>et al. </i>Nano Letts 5, 2528-2532 (2005).<br/>[2] (Review) J. Wang, <i>et al.</i>, Nanoscale 2, 2028-2034 (2010).<br/>[3] C. H. Lee,<i> et al</i>. Advanced Materials 25, 4544-4548 (2013).<br/>[4] S. Bhandari, <i>et al.</i> ACS Nano 13, 4347-4353 (2019).<br/>[5] J-K Qin, <i>et al.</i> Nature Electronics 3, 141-147 (2020).<br/>[6] Y. K. Yap, D. Zhang, N. B. Yapici, US Patent Application US20180296705A1.<br/>[7] (Review) D. Zhang, <i>et al.</i> ACS Omega 6, 20722-20728 (2021).<br/>[8] (Review) D. Zhang, <i>et al. </i>J. Maters. Res. (Submitted)<br/><br/>We acknowledge the support from the Department of Energy, the National Science Foundation, and the Center for Nanophase Materials Sciences (CNMS) at Oak Ridge National Laboratory.