Nano Letters

Mapping active dopants in single silicon nanowires using off-axis electron holography

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We demonstrate that state-of-the-art off-axis electron holography can be used to map active dopants In silicon nanowires as thin as 60 nm with 10 nm spatial resolution. Experiment and simulation demonstrate that doping concentrations of 1019 and 1020 cm 3 can be measured with a detection threshold of 1018 cm 3 with respect to intrinsic silicon. Comparison of experimental data and simulations allows an estimation of the charge density at the wire-oxide interface of -1 × 1012 electron charges cm 2. Off-axis electron holography thus offers unique capabilities for a detailed analysis of active dopant concentrations In nanostructures. © 2009 American Chemical Society.