Abstract
The electronic and optical properties of graphene are greatly dependent on the the number of layers. For the precise control of the graphene layers, atomic layer etching (ALE), a cyclic etching method achieved through chemical adsorption and physical desorption, can be the most powerful technique due to barely no damage and no contamination. In this study, we demonstrated the ALE process of graphene layers without noticeably damaging the graphene by using a controlled low energy oxygen (O2+/O+)-ion for chemical adsorption and a low energy Ar+-ion (11.2 eV) for physical desorption. In addition, using a trilayer graphene, mono- and bi-layer graphene could be successfully fabricated after one- and two-cycle ALE of the trilayer graphene, respectively. We believe that the ALE technique presented herein can be applicable to all layered materials such as graphene, black phosphorous and transition metal dichalcogenides which are important for next generation electronic devices.
Highlights
Graphene has attracted considerable attention due to their unique properties including very high electron mobility, extremely high mechanical strength, superior thermal conductivity, and high chemical stability[1,2,3,4]
Using an optimized Atomic layer etching (ALE) process composed of a controllable low energy oxygen(O2+/O+)-ion for chemical adsorption and a low energy Ar+-ion beam for physical desorption, we were able to achieve a precise control of graphene layers without damage on the bottom graphene layer
To precisely control the graphene layers without inducing damage, we introduced a graphene ALE process, a cyclic etch process composed of chemical adsorption by a low energy oxygen (O2+/O+)-ion (0~20 eV) and followed physical desorption of the chemisorbed species by a low energy Ar+-ion beam (11.2 eV)
Summary
Graphene has attracted considerable attention due to their unique properties including very high electron mobility, extremely high mechanical strength, superior thermal conductivity, and high chemical stability[1,2,3,4]. Atomic layer etching (ALE), a cyclic etch method composed of chemical adsorption and physical desorption of the sequential steps, is one of the techniques that have good potential in precisely removing graphene layer-by-layer without inducing damage and contamination. It is applicable for the nanoscale device fabrication because it removes graphene layers after photoresist patterning using coventional patterning methods. Using the low energy Ar+-ion, the polymer residue layer could be completely removed in this study before the ALE process without damaging the graphene surface[20, 21]
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