Scanning probe microscopy for optoelectronic characterization at the nanoscale

In this work, we propose methods for electrical characterization of nanostructured surfaces using electrostatic force and tunneling current measurements in scanning probe microscopy. Resolution smaller than 10 nm in electrostatic force microscopy (EFM) is attained and reasons for this attainment is explained in terms of the tip-sample capacitance and mechanical vibrations of tip design. Dynamic measurements are done in EFM using a lumped model for tip-sample electrostatic interaction instead of a simple tip-sample capacitance model. Surface photovoltage measurements are done and assured in EFM using frequency response techniques. Also, combining tunneling current measurements by EFM measurements, optoelectonic properties of graphene/graphene oxide samples are characterized.