Graphene samples can have a very high carrier mobility if influences from thesubstrate and the environment are minimized. Embedding a graphene sheet into aheterostructure with hexagonal boron nitride (hBN) on both sides was shown tobe a particularly efficient way of achieving a high bulk mobility.Nanopatterning graphene can add extra damage and drastically reduce samplemobility by edge disorder. Preparing etched graphene nanostructures on top ofan hBN substrate instead of SiO2 is no remedy, as transport characteristics arestill dominated by edge roughness. Here we show that etching fully encapsulatedgraphene on the nanoscale is more gentle and the high mobility can bepreserved. To this end, we prepared graphene antidot lattices where we observemagnetotransport features stemming from ballistic transport. Due to the shortlattice period in our samples we can also explore the boundary between theclassical and the quantum transport regime.
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