Quantitative measurement of local conductivity of SnO2 nanobelt field effect transistor utilizing microwave atomic force microscopy

A non-contact quantitative method for measuring the electrical conductivity of a SnO2 nanobelt field-effect transistor (FET) with nanometer-scale spatial resolution is reported. The topography and microwave images of the nanobelt FET were measured by microwave atomic force microscopy (M-AFM) under a constant source voltage and different back-gate voltages. The output characteristics of the nanobelt FET were measured using a two-probe measurement method. The local conductivity of the SnO2 nanobelt FET measured by M-AFM concurred with that obtained by the two-probe measurement. Therefore, M-AFM is a promising method for measuring the local conductivity of nanomaterial FETs.