Gold particles on carbon film

This high resolution TEM test specimen is an arrangement of finely-dispersed thin gold particles on carbon film. As with gold foil, image quality, magnification, and instrument stability are readily assessed; however, for the determination of resolution capabilities this gold particle specimen is superior since it offers a choice of crystalline orientation on static or low tilt stages. In addition, the thickness of the crystalline material is easily calculated from the projected shape of the gold crystal. The background noise arising from structure in the support film helps with determinations of the operating transfer function.

The gold particles on this carbon film have a size distribution which is nominally in the range 2nm to 9nm. The smallest particles are less suitable for high resolution tests than the larger ones. It appears that the larger particles often join together and produce the morphological effect seen in the above micrograph. Since the thickness of these particular crystals is highly suitable for stronger diffraction, these are the particles that should be used in the first instance.