A key enabler for atomic-force microscopy is the ability to sense the cantilever motion with high resolution and high bandwidth. We are developing new techniques for cantilever / sample motion sensing that maintain the high resolution of optical sensing but obviate its inherent size and cost drawbacks.
In semiconductor device research, there is a significant need for the nanoscale electrical characterization of materials. Several scanning probe techniques can be used to obtain a reliable measure of local resistance, surface potential and capacitance in addition to topography maps.
Scanning probe techniques can also be used to study the electrical transport in materials at the nanoscale. Our work on conductive-mode atomic force microscopy addresses these nanoscale electrical characterization needs.
In recent years, several modes of operation have been proposed for atomic force microscopy, collectively known as multi-frequency AFM (MF–AFM). Examples include amplitude-modulation AFM (AM–AFM), which utilize higher harmonics, higher resonant modes and multiple modes. We are using system-theoretic tools to develop techniques for quantitative MF–AFM.