Title: Optically Coupled Methods for Microwave Impedance Microscopy,
Abstract: Scanning Microwave Impedance Microscopy (MIM) measurement of
photoconductivity with 50 nm resolution is demonstrated using a modulated
optical source. The use of a modulated source allows for measurement of
photoconductivity in a single scan without a reference region on the sample, as
well as removing most topographical artifacts and enhancing signal to noise as
compared with unmodulated measurement. A broadband light source with tunable
monochrometer is then used to measure energy resolved photoconductivity with
the same methodology. Finally, a pulsed optical source is used to measure local
photo-carrier lifetimes via MIM, using the same 50 nm resolution tip.