KPFM of nanostructured electrochemical sensors

Integrating sensor arrays with microelectronic devices enables applications such as disease diagnostics and environmental monitoring. The most advanced chemical sensor concepts, compatible with integrated circuits, comprise a semiconductor with a nanostructured sensing area that can be modified to be more selective and sensitive to specific analytes. The target molecules react with the exposed surface area and may dope the semiconductor, alter the surface charge density, and polarize the surface, which in turn affects the current that flows through the semiconductor via field-effect and charge transfer. KPFM allows probing the smallest variations of the surface charge density and band bending on a nanometer scale. Unique in this sense, KPFM can be used to detect the work function changes following adsorption and map the potential landscape of a nanostructured sensor surface to locate the most sensitive region. The chapter describes how KPFM helps to advance research and development of chemical sensors.