Nanopatterning Hexagonal Boron Nitride with Helium Ion Milling: Towards Atomically-Thin, Nanostructured Insulators
- PDF / 677,409 Bytes
- 5 Pages / 432 x 648 pts Page_size
- 73 Downloads / 162 Views
MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.117
Nanopatterning Hexagonal Boron Nitride with Helium Ion Milling: Towards Atomically-Thin, Nanostructured Insulators S. Matt Gilbert1,2,3, Stanley Liu1,3, Gabe Schumm1,3, Alex Zettl1,2,3 1
Department of Physics, University of California, Berkeley, CA, 94720
2
Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720
3
Kavli Energy Nanosciences Institute, Berkeley, CA, 94720
ABSTRACT
In this report, we demonstrate the use of helium ion milling for the controllable fabrication of nanostructures in few-layer hexagonal boron nitride (h-BN). Using the direct-write lithographic capabilities of a scanning helium ion microscope (HIM), nanopores with diameters as small as 4 nm and nanoribbons with widths of 3 – 10 nm are etched from suspended h-BN sheets. This ability to pattern h-BN sheets with high-throughput and sub-10 nm precision paves the way for future studies that make use of atomically-thin, nanostructured insulators such as those needed for nanopore sequencing and patterned van der Waals heterostructures.
INTRODUCTION Few-layer hexagonal boron nitride (h-BN) has emerged as an important material in the study of heterostructures of twodimensional (2D) materials [1-3], and its many unique properties suggest a variety of stand-alone applications [4-7]. As an atomically-thin and chemically-inert sp2 hybridized insulator, h-BN is an ideal substrate and encapsulation layer for graphene and transition metal dichalcogenides (TMDs) [1,3,8,9]. Its flat surface and lack of dangling bonds reduce substrate-induced scattering for encapsulated 2D materials, and its impermeability prevents oxidation of these encapsulated layers [7, 8, 10, 11]. The ability to pattern and etch h-BN has been explored for a variety of purposes to aid in its role in graphene electronics. Patterned h-BN has been demonstrated as a growth template for CVD graphene [12]. Stacks of h-BN/graphene/h-BN have been etched to create edge contacts for the encapsulated graphene [11, 13]. Holes through h-BN stacked on graphene have been used to create point contacts for the graphene [14]. Moreover, nanostructures in insulating materials are being studied for their role in the production of superlattices in two-dimensional materials; the ability to pattern and etch h-BN for this purpose could enhance the results in the existing literature by moving the electronic 2D material closer to the periodic potential [15]. The patterning and etching of h-BN has also been studied for several stand-alone applications. Nanopores etched in h-BN have been shown to confer several advantages for DNA sequencing over their graphene counterparts [4, 16]. h-BN nanoribbons etched from boron nitride nanotubes have also been explored due to their interesting magnetic and electronic properties [17-19]. Here we demonstrate the use of helium ion milling for the controlled fabrication of nanostructures in few-layer h-BN. Specifically, we show using a direct-write lithographic system that
Data Loading...
