Effects of chemical modification using Au or I ion beam irradiation on the carrier transport properties of graphene

Abstract

Graphene in its isolated form is a promising material for applications in next-generation electronic devices; however, a strategy for modifying graphene to tune its carrier transport properties to meet requirements related to carrier density, electron mobility, and spin-orbit coupling is needed. We have modified graphene by irradiating it with a Au- or I-ion beam at 200 keV with doses of 10¹³–10¹⁴ cm⁻² using a NaCl sacrificial layer as a quantitative chemical modification method. Ion-irradiated graphene was evaluated by Raman spectroscopy, electrical conductivity measurements, and Rutherford backscattering spectrometry after removing the sacrificial layer. Both carbon vacancies and heavy atoms (Au, I) are introduced into graphene by ion-beam irradiation; the introduced heavy atoms act as charged impurities, which results in the Raman D′ band and a downshift of the Fermi energy caused by hole carrier doping. Clearer knowledge of the influence of heavy-ion beam irradiation of graphene on electron transport properties will lead to the development of a new class of materials for electronics and spintronics.