Pulsed lasers extend the high spatial and mass resolution of atom probe tomography (APT) to non-conducting materials, such as oxides. For prototypical metal oxide MgO, measured stoichiometry depends strongly upon pulse energy and applied voltage. Very low laser energies (0.02 pJ) and high electric fields yield optimal stoichiometric accuracy, attributed to the field-dependent ionization of photo-desorbed O or O2 neutrals. This emphasizes the importance of considering electronic excitations in APT analysis of oxides ionic materials.
Revised: March 28, 2013 |
Published: March 6, 2013
Citation
Devaraj A., R.J. Colby, W.P. Hess, D.E. Perea, and S. Thevuthasan. 2013.Role of Photoexcitation and Field Ionization in the Measurement of Accurate Oxide Stoichiometry by Laser-Assisted Atom Probe Tomography.The Journal of Physical Chemistry Letters 4, no. 6:993-998.PNNL-SA-92674.doi:10.1021/jz400015h