Triebenberg Laboratory, Institute of Structure Physics, Technische Universität Dresden, 01062 Dresden, Germany.
Ultramicroscopy. 2010 Apr;110(5):390-9. doi: 10.1016/j.ultramic.2009.12.015. Epub 2010 Jan 13.
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 0.5V was obtained.
电子全息断层扫描（EHT），即离轴电子全息术与电子断层扫描的结合，成功地应用于纳米尺度静电势的定量 3D 映射。这里我们提出了第一个用于半自动获取全息倾斜系列的软件包（THOMAS），这是高效数据采集的前提。使用 THOMAS，与以前完全手动的方法相比，由物体和参考全息图组成的全息倾斜系列的采集时间平均减少了五倍。此外，用于从电子全息图中检索幅度和相位信息的现有软件包已经扩展，现在包括用于全息倾斜系列重建的一步程序。此外，还实现了一种改进的 SIRT 算法（WSIRT），用于从对齐的相位倾斜系列定量重建静电势。最后，展示了 EHT 在聚苯乙烯乳胶球测试样本和 pn 掺杂 Ge“针”状样本中的应用，说明了 EHT 的定量性质。对于两个样本，均从重建的 3D 电势中准确地确定了平均内电势（MIP）值。对于 Ge 样本，还获得了 pn 结的“内置”电压 0.5V。
