Prof. J. Colchero

Universidad de Murcia,

Facultad de Química

Centro de Investigación en Ópica y Nanociencia (CIOyN)

Departamento de Física

Campus Universitario de Espinardo, E-30100 – Murcia

SPAIN

Electrostatic Scanning Force Microscopy:

Electric fields as powerful tools for nanoscale material characterization

In Electrostatic Scanning Force Microscopy a voltage difference applied between a sharp tip and the sample induces electrical forces that critically depend on the precise properties of the sample (but also of the tip). From the correct modelling of the tip-sample system and a correct interpretation of these forces in principle a wealth of information can be extracted. In our group we are trying to understand in detail the precise electrical response of the tip-sample system to make Electrostatic and Kelvin Force Microscopy a quantitative nanoelectronic instrument. The basic principles of Electrostatic and Kelvin Force Microscopy, will be described, we will point towards what we believe to be its main challenges, and finally, we will try to motivate the great potential that a well-established technique should provide for nanoelectronics. Experiments will be presented in order to demonstrate the capability of nanoscale electrical characterization of samples in air and liquids. In particular, we will show, on the one hand, howthe time evolution of the surface potential of an organic polymer can be studied. On the other hand, we will discuss how the simultaneous measurement of amplitude, force and frequency shift (or phase) allows accessing the electrostatic force induced by the Electrical Double Layer, and thus the surface charge in liquid environment (see figure).

Prof. Jaime Colchero is group leader of the research group “Devices, Investigation and Applications in Nanoscience” (DIANA) at the Centre for Optics and Nanoscience of the Universidad de Murcia. He graduated in Physics at the University of Bonn (1988). His PhD-thesis was carried out at the ETH Zürich and University of Konstanz (1993). During this thesis, he firstly developed Scanning Force and Friction Microscopy and investigated the membrane protein Na,K-ATPase in liquid environment. After his PhD thesis, Dr. J. Colchero moved to the “Laboratorio de Nuevas Microscopías” at Universidad Autónoma de Madrid first as a postdoctoral researcher and later as lecturer and assistant professor. In 2001 he moved to the Universidad de Murcia as professor, where he founded the DIANA research group.

J. Colchero is involved in the development of a variety of AFM measuring modes, including static and dynamic friction microscopy, low oscillation (non-contact) Dynamic AFM, and in particular Electrostatic and Kelvin Force Microscopy. Recently, the group has been involved in different aspects of multifrequency AFM, and has developed a flexible combined AFM-optical microscopy system. The main research lines of the DIANA research group are twofold: focusing on the investigation and development of scanning probe microscopy on the one hand, and on the application of these techniques to different fields of (nano-) Science on the other.