Atomic structure of beta-tantalum nanocrystallites
by Karsten Tillmann, Andreas Thust, Andreas Gerber, Martin P. Weides, and Knut Urban
The structural properties of beta-phase tantalum nanocrystallites prepared by room temperature magnetron sputter deposition on amorphous carbon substrates have been investigated at atomic resolution. For these purposes spherical aberration-corrected high-resolution transmission electron microscopy has been applied in tandem with the numerical retrieval of the exit-plane wavefunction as obtained from a through-focus series of experimental micrographs.
It has been demonstrated that recent improvements in the resolving power of electron microscopes enable the imaging of the atomic structure of beta-tantalum with column spacings of solely 0.127 nm with directly interpretable contrast features. For the first time ever, the existence of grain boundaries of 30° tilt type in beta-tantalum has been substantiated whose formation may be well explained by atomic agglomeration processes taking place during sputter deposition.
Further reading: Microscopy & Microanalysis 11 (2005) 534-544