The surface quality of the thin films is tested using either atomic force microscopy (AFM) or scanning tunnelling microscopy (STM).
Atomic Force Microscopy
The next tree images are AFM images with lateral size respectively of 1.6 μm x 1.6 μm, 1.1 μm x 1.1 μm and 1.1 μm x 1.1 μm. The z scale is 5 nm for the first image and 3 nm for the last two.
Scanning Tunneling Microscopy
The next image is a 0.5 μm x 0.5 μm STM image of a 2 month old sample kept inside its box. The Z scale is 2 nm.
The size of the terraces may vary from one sample to another. We observe sometime terraces as large as 1 μm2. During the production process, we regularly control the surface quality of our films.