Fig. 3

Comparison of experimental and simulated MEM contrast. (Top row) sequence of experimental images of various stages of droplet epitaxy at the indicated times [20]. (Bottom row) sequence of simulated MEM images at a defocus of \( \Delta f=-42\;\upmu \mathrm{m} \), electron initial energy \( U=20 \) keV, L = 2 mm, cathode potential of \( V=-20,000.4 \)V and liquid Ga work function difference of −0.3 V. The simulations used 1201 rays with initial spacing \( {x}_0=10 \) nm, with the intensity calculated using Eq. 2. The height profiles used for each of the four time steps are shown in Fig. 5 and were based on AFM traces of representative stages of droplet epitaxy (Fig. 4)