Quartz tuning fork-based conductive atomic force microscope with glue-free solid metallic tips

• A non-contact conductive-AFM system has been developed.
• A glue-free W tip and a quartz tuning fork have been used in the experiments.
• The mechanical stability of the system is ensured by a specifically designed header.
• Simultaneous topographical and electrical images show the potential of the system.

Here, we devise a conductive Atomic Force Microscope (C-AFM) based on quartz tuning forks (QTFs) and metallic tips capable of simultaneously imaging the topography and conductance of a sample with nanoscale spatial resolution. The system is based on a header design which allows the metallic tip to be placed in tight and stable mechanical contact with the QTF without the need to use any glue. This allows electrical measurements to be taken with an electrically excited QTF with the two prongs free. The amplitude oscillation of the QTF is used to control the tip-sample distance and to acquire the topographic images. Meanwhile, the metallic tip is connected to a current–voltage amplifier circuit to measure the tip-sample field emission/tunneling current and to produce the conductive images. This method allows decoupled electrical measurement of the topography and electrical properties of the sample. The results we obtain from calibration samples demonstrate the feasibility of this measurement method and the adequacy of the performance of the system.