Frequency-dependent transport imaging by scanning probe microscopy

Abstract

Frequency-dependent transport measurement, including impedance spectroscopy and capacitance-voltage measurement, is a key tool for materials and device characterization and failure analysis. The rapid development of nanomaterials and nanoscale devices necessitates extending our fundamental understanding of transport phenomena to the nanoscale as well. The ability to conduct nanoscale impedance measurements provides a promising route to extend our understanding of nanoscale transport physics and device operation. In this chapter, we describe two paradigms for scanning probe microscopy (SPM)-based impedance measurement [1-5]. In a first configuration, the SPM tip is used as a current probe in a manner similar to conventional impedance spectroscopy (nanoimpedance microscopy). In a second configuration, the SPM tip is used as a moving voltage electrode in a manner similar to four probe impedance measurements (scanning impedance microscopy). Applying these two configurations, nanometer scale measurement and visualization of impedance is demonstrated for a wide variety of materials systems, including solid electrolytes, semiconductors, electroceramics, corrosion research, and fuel cell systems. Future prospects for SPM-based impedance measurement are discussed. © 2007 Springer Science+Business Media, LLC.