Local Molecular Desorption-induced Carrier Density Modulation in Graphene Measured Using Nitrogen Vacancy Centers in Nanodiamonds

Abstract

We investigate photoinduced carrier modulation in graphene field-effect transistors by measuring the local Oersted magnetic field using nitrogen vacancy centers in nanodiamonds. The observed change in the Oersted magnetic field during measurement is attributed to laser-induced molecular desorption, which creates a local carrier density gradient in the graphene channel. This result is consistent with the laser-induced variations in the electronic transport properties. The method employed in this study enables visualization of local molecular adsorption-desorption dynamics with higher spatial resolution than conventional optical techniques, which are limited by the diffraction limit of light.