Focal-series reconstruction in HRTEM: simulation studies on non-periodic objects

The reliability of focal-series reconstruction algorithms for the retrieval of the wavefunction at the exit plane of the object (exit-plane wavefunction) is investigated for the case of non-periodic object features. Simulated high-resolution electron microscope images of an abrupt GaAs/AlAs interface and of an edge dislocation in GaAs are chosen as test cases. The reconstruction schemes employed for the retrieval of the exit-plane wavefunction are the so-called “paraboloid method” (PAM) and the “maximum likelihood” method (MAL) which have been developed to application stage within the framework of the BRITE-EURAM project No. 3322. Special attention is given to the convergence behavior of the algorithms in the presence of noise and under highly non-linear imaging conditions.