Peculiarities of imaging one- and two-dimensional structures in an emission electron microscope. 1. Theory

Local changes in work function cause deviations of the electrical microfiel d near a sample surface as a result of the uniform accelerating field distr ibution between the sample (cathode) and the extractor electrode (anode). T his results in a change in the electron trajectories. As a consequence, the microscope image shows remarkable changes in position, size, intensity and lateral resolution of distinct details, which can be quantitatively descri bed by the calculations presented here. Analysing these effects in the imag e gives an opportunity to determine the real lateral size of the observed s tructures and the distribution of local contact potentials.