Nanometer-scale Tomographic Reconstruction of 3D Electrostatic Potentials in GaAs/AlGaAs Core-Shell Nanowires

TL;DR

This paper presents a novel electron holographic tomography method that achieves high-resolution 3D electrostatic potential mapping in nanowires, overcoming previous limitations in tilt range and automation.

Contribution

It introduces an automated, symmetry-aware tomographic reconstruction technique that significantly improves spatial resolution and accuracy in 3D potential measurements of nanostructures.

Findings

Achieved 6 nm spatial resolution in potential mapping

Demonstrated 0.2 V signal resolution in nanowire potentials

Enabled detection of previously hidden potential details

Abstract

We report on the development of Electron Holographic Tomography towards a versatile potential measurement technique, overcoming several limitations, such as a limited tilt range, previously hampering a reproducible and accurate electrostatic potential reconstruction in three dimensions. Most notably, tomographic reconstruction is performed on optimally sampled polar grids taking into account symmetry and other spatial constraints of the nanostructure. Furthermore, holographic tilt series acquisition and alignment have been automated and adapted to three dimensions. We demonstrate 6 nm spatial and 0.2 V signal resolution by reconstructing various, previously hidden, potential details of a GaAs/AlGaAs core-shell nanowire. The improved tomographic reconstruction opens pathways towards the detection of minute potentials in nanostructures and an increase in speed and accuracy in related techniques such as X-ray tomography.