Probing of Surface Potential Using Atomic Force Microscopy

Abstract

Surface electrical properties are being interest for many different applications including solar cell (Coffey & Ginger, 2006; Yoo et al., 2014) and information technologies (Vasudevan et al., 2013). Recently, as decreasing device size, nanoscale surface properties become more significant. In particular, since surface potential is directly relevant to work function of materials and/or surface charge, nanoscale probing of surface potential has paid much attention for understanding various surface phenomena such as photovoltaic phenomena, screening behavior of ferroelectric surfaces, and work function and surface states of semiconducting materials (Takahashi et al., 2000; Kalinin & Bonnell, 2001, 2004; Hong et al., 2009). The nanoscale probing of surface potential is still challengeable. In fact, atomic force microscopy (AFM) is a well know technique which allows exploring nanoscale material properties. Among various AFM modes, electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM) allow us probing surface potential in many different types of materials including metal, ceramic, and organic materials at the nanoscale (Ellison et al., 2011). We review operational mechanisms of EFM and KPFM which allow exploring surface potential at the nanoscale. Also, we discuss advantages and disadvantages of each technique and show some of experimental examples of these AFM modes.