Effect of E-beam irradiation on graphene sandwiched between h-BN layers

Abstract

The potential of graphene for electronic applications originates owing to its exceptional room temperature carrier mobility. However, during the fabrication of electronic devices like field-effect transistors graphene is exposed to external environment that affects its carrier mobility. Also, the formation of dangling bonds at Si/SiO2 interface further degrades the mobility of graphene and hence influence the performance of graphene devices. In order to protect graphene from environmental conditions and preserve its fundamental electrical properties in such devices, here graphene is sandwiched between hBN layers (i.e. hBN/Graphene/hBN) and then the effect of e-beam irradiation on graphene structure is studied. To investigate structural disorder in graphene, Raman analysis was carried out which revealed no defects in graphene even for a high dose of e-beam irradiation. The electrical and magneto-transport measurements further confirmed the stability of these e-beam irradiated hBN-passivated graphene devices thereby demonstrating a mobility of 16,638 cm2/Vs and Quantum Hall plateaus at 9 T, respectively. Furthermore, different devices comprising Graphene/SiO2, Graphene/hBN and hBN/Graphene/hBN are studied for the interface analysis, which after e-beam irradiation revealed no defects and contaminations at the interfaces between hBN and graphene.