Probing nanoscale objects in liquids through membranes with near-field microwave microscopy

In this work, scanning near-field microwave imaging was implemented to test the feasibility of the approach for in-situ studies of nanoscale objects immersed in liquids under thin dielectric membranes. It was found that mechanical strength and stability of SiN membranes on Si frames are sufficient for contact mode imaging in a standard AFM setup. Model polystyrene particles immersed in glycerol in contact with the membrane from the cavity side could be reliably detected. The probing depth of this imaging mode can be estimated to be approximately 100 nm.