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

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.