TY - JOUR
T1 - Towards automated electron holographic tomography for 3D mapping of electrostatic potentials
AU - Wolf, Daniel
AU - Lubk, Axel
AU - Lichte, Hannes
AU - Friedrich, Heiner
PY - 2010/4
Y1 - 2010/4
N2 - Electron-holographic tomography (EHT), that is, the combination of off-axis electron holography with electron tomography, was successfully applied for the quantitative 3D mapping of electrostatic potentials at the nanoscale. Here we present the first software package (THOMAS) for semi-automated acquisition of holographic tilt series, a prerequisite for efficient data collection. Using THOMAS, the acquisition time for a holographic tilt series, consisting of object and reference holograms, is reduced by a factor of five on average, compared to the previous, completely manual approaches. Moreover, the existing software packages for retrieving amplitude and phase information from electron holograms have been extended, now including a one-step procedure for holographic tilt series reconstruction. Furthermore, a modified SIRT algorithm (WSIRT) was implemented for the quantitative 3D reconstruction of the electrostatic potential from the aligned phase tilt series. Finally, the application of EHT to a polystyrene latex sphere test-specimen and a pn-doped Ge 'needle'-shaped specimen are presented, illustrating the quantitative character of EHT. For both specimens the mean inner potential (MIP) values were accurately determined from the reconstructed 3D potential. For the Ge specimen, additionally the 'built-in' voltage across the pn junction of 0.5. V was obtained.
AB - Electron-holographic tomography (EHT), that is, the combination of off-axis electron holography with electron tomography, was successfully applied for the quantitative 3D mapping of electrostatic potentials at the nanoscale. Here we present the first software package (THOMAS) for semi-automated acquisition of holographic tilt series, a prerequisite for efficient data collection. Using THOMAS, the acquisition time for a holographic tilt series, consisting of object and reference holograms, is reduced by a factor of five on average, compared to the previous, completely manual approaches. Moreover, the existing software packages for retrieving amplitude and phase information from electron holograms have been extended, now including a one-step procedure for holographic tilt series reconstruction. Furthermore, a modified SIRT algorithm (WSIRT) was implemented for the quantitative 3D reconstruction of the electrostatic potential from the aligned phase tilt series. Finally, the application of EHT to a polystyrene latex sphere test-specimen and a pn-doped Ge 'needle'-shaped specimen are presented, illustrating the quantitative character of EHT. For both specimens the mean inner potential (MIP) values were accurately determined from the reconstructed 3D potential. For the Ge specimen, additionally the 'built-in' voltage across the pn junction of 0.5. V was obtained.
KW - Acquisition software
KW - Automation
KW - Electron holography
KW - Electron tomography
KW - Electrostatic potential
KW - Reconstruction algorithm
UR - http://www.scopus.com/inward/record.url?scp=77952321756&partnerID=8YFLogxK
U2 - 10.1016/j.ultramic.2009.12.015
DO - 10.1016/j.ultramic.2009.12.015
M3 - Article
C2 - 20106597
AN - SCOPUS:77952321756
VL - 110
SP - 390
EP - 399
JO - Ultramicroscopy
JF - Ultramicroscopy
SN - 0304-3991
IS - 5
ER -