Tuesday, April 23, 2013

Interpreting Kelvin probe force microscopy under an applied electric field: local electronic behavior of vapor–liquid–solid Si nanowires

Nathaniel J Quitoriano, Robert N Sanderson, Sung-Soo Bae and Regina Ragan



Kelvin probe force microscopy (KPFM) is used to characterize the electrical characteristics of vapor–liquid–solid (VLS) Si nanowires (NWs) that are grown in-place between two predefined electrodes. KPFM measurements are performed under an applied bias. Besides contact potential differences due to differing materials, the two other primary contributions to measured variations on Si NWs between electrodes are: trapped charges at interfaces, and the parallel and serial capacitance, which are accounted for with voltage normalization and oxide normalization. These two normalization processes alongside finite-element-method simulations are necessary to characterize the bias-dependent response of Si NWs. After applying both normalization methods on open-circuit NWs, which results in a baseline of zero, we conclude that we have accounted for all the major contributions to CPDs and we can isolate effects due to applied bias such as impurity states and charged carrier flow, as well as find...



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