Miniaturization of silicon field effect transistors (FETs) is encounter with various fundamental limitations, including i) high power consumption due to leakage in the semiconducting channels; ii) short channel effects as the conduction length approaches the scale of the depletion layer width, and iii) high contact resistance at the semiconducting channels. The development of nano FETs by various nanowires (NWs), and carbon nanotubes (CNTs) are still hindered by surface defects and difficulty in controlled synthesis of semiconducting CNTs, respectively.

Apparently, beyond the box approaches should be explored to overcome the above mentioned limitations. Here we discuss about creation of transistors and electronic switches without semiconductors. Furthermore, these devices are based on quantum tunneling, potentially bypass most if not all the above mentioned limitation. Specifically, we will discuss about room temperature tunneling FETs by metallic quantum dots functionalized boron nitride nanotubes (QDs-BNNTs) [1]. These QDs-BNNTs can also be designed for use in flexible electronics [2]. Finally, graphene-BNNTs heterojunctions are also created to convert metallic graphene into digital switches [3]. All these results are made possible after the success in controlled synthesis of high-quality BNNTs by catalytic chemical vapor deposition (CCVD) [4-6].

This work is supported by the U.S. Department of Energy, the Office of Basic Energy Sciences (DOE-BES Grants DEFG0206ER46294, and DESC0012762). Part of this work was conducted at the Center for Nanophase Materials Sciences (Projects CNMS-2009213 and CNMS-2012083), which is sponsored at Oak Ridge National Laboratory (ORNL) by the DOEBES Scientific User Facilities Division, and by ORNL’s Shared Research Equipment (ShaRE) User Program.

References:
[1] C. H. Lee et al, Adv Mat 25, 2544 (2013).
[2] B. Hao et al, Sci Rep 6, 20293 (2016).
[3] V. Parashar et al, Sci Rep 5, 12238 (2015).
[4] (Review) J. Wang et al, Nanoscale 2, 2028 (2010)
[5] (Review) B. Hao et al, Chapter 20 in Nanotubes and Nanosheets: Functionalization and Applications of Boron Nitride and Other Nanomaterials, (CRC Press) pp 551-572 (2015).
[6] (Review) S. Bhandari et al, Chapter 1 in Boron Nitride Nanotubes in Nanomedicine, (Elsevier) pp 116 (2016).