Quantitative atom counting of Zn and O atoms by atomic resolution off-axis and in-line holography

TL;DR

This paper demonstrates quantitative atom counting of Zn and O in ZnO thin films using atomic resolution electron holography, comparing off-axis and in-line methods, and discusses phase detection limits and atomic models.

Contribution

It introduces a method for quantitative atom counting in ZnO thin films using electron holography and compares off-axis and in-line approaches for accuracy.

Findings

Reconstructed phase from off-axis holography agrees with atom counts in thin regions.

Discrepancies occur in thicker sample areas with off-axis holography.

In-line holography shows no systematic phase change with thickness.

Abstract

Quantitative atom counting of Zn and O atoms in zinc oxide(ZnO)epitaxial thin film by three different routes; reconstruction of phase from side and central band of atomic resolution off-axis and in-line electron holography are presented. It is found that the reconstructed phase from both side and central band and corresponding atom number for both Zn (Z = 30) and O (Z = 8) atom columns are in close agreement along with the systematic increase in thickness for thinner sample area.However, complete disagreement is observed for the thicker sample area. On the other hand,the reconstructed phase obtained via in-line holography shows no systematic change with thickness.Phase detection limits and atomic model used to count the atoms are discussed.