Defect Control and n-Doping of Encapsulated Graphene by Helium-Ion-Beam Irradiation.

Nanda, Gaurav; Goswami, Srijit; Watanabe, Kenji; Taniguchi, Takashi; Alkemade, Paul F A · Nano Lett · 2015

basic_science · Level V

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Abstract

We study with Raman spectroscopy the influences of He(+) bombardment and the environment on beam-induced defects in graphene encapsulated in hexagonal boron nitride (h-BN). We show for the first time experimentally the autonomous behavior of the D' defect Raman peak: in contrast to the D defect peak, the D' defect peak is sensitive to the local environment. In particular, it saturates with ion dose in the encapsulated graphene. Electrical measurements reveal n-type conduction in the BN-encapsulated graphene. We conclude that unbound atoms ("interfacials") between the sp(2)-layers of graphene and h-BN promote self-healing of the beam-induced lattice damage and that nitrogen-carbon exchange leads to n-doping of graphene.