Directional etching for high aspect ratio nano-trenches on hexagonal boron nitride by catalytic metal particles

Abstract

Abstract Stimulated by the attractive performance of multi-dimensional heterostructures involving hexagonal boron nitride ( h BN), intense attentions have been paid to creation of sharp boundary/interface, which could bring h BN nano-structures additional appealing physical properties. However, the lack of controllable synthesis limits further experimental investigation on h BN nano-structures. Here, the directional etching of transitional metal nano-particles (NPs) on the surface of h BN to produce nano-trenches with sharp edges was systematic investigated. It is found that, only Pt and Ir NPs can produce armchair-oriented nano-trenches at low H 2 partial pressure, while other transitional metals lead to zigzag oriented nano-trenches. The density and width of the nano-trenches always increase with etching temperature and the pre-treated solution concentration while the trench orientation depends on both H 2 partial pressure and etching temperature. The aspect ratio of nano-trenches may reach several thousand under optimized conditions. The method exhibited here shines a light on edge-selective patterning of 2D crystals.