Mapping electrostatic profiles across axial p-n junctions in Si nanowires using off-axis electron holography

Si nanowires (NWs) with axial p-n junctions were grown by the vapor-liquid-solid method. Transmission electron microscopy and electron holography were used to characterize the microstructure and electrostatic properties. Measurement of the potential profile showed the presence of a p-n junction with a height of 1.0 ± 0.3 V. A Schottky barrier was observed at the end of the NW due to the Au catalyst particle. Comparison with simulations indicated dopant concentrations of 1019 cm−3 for donors and 1017 cm−3 for acceptors. These results confirm the benefit of combining off-axis electron holography with simulations for determining localized information about the electrically active dopant distributions in nanowire structures.