Near-field scanning Raman microscopy for nano-science and nano-technology

IV-12: Near-field scanning Raman Microscopy for Nano-science and Nano-technology

Shen Zexiang, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences

Abstract

Near-field scanning Raman microscopy provides chemical/structural specific information with nanometer spatial resolution, which are critically important for a wide range of applications, e.g. nano-structures, CNT, quantum dots, single molecules of biological samples. The traditional approach using optical fibers has very limited use due to its extreme low signal level. In this talk, we describe our near-field Raman study using apertureless probes. Our system has two important features, critical to practical applications. (1) The near-field Raman enhancement was achieved by Ag coating of the metal probes, without any sample preparation; (2) the system works in reflection geometry, making it applicable to any samples. We have obtained the first 1-D Raman mapping and 2D near-field Raman image of a real Si device with 1s integration time. This is the first demonstration that this technique can be used for imaging purpose because of short integration time. The metal tips used in our set-up can be utilized to make simultaneous AFM and electrical mappings e.g. resistance and capacitance that are critical in device applications.