A <110 > -oriented cross-sectional sample was thinned by mechanical polishing and ion milling.
The results showed that the whole thickness of the pre-oxidised sample was thinner than that of the controlled one.
Thin specimens for TEM observation were prepared by Ar-ion thinning by the following procedure: the graphene-on-SiC samples were mechanically ground to 70 μm thick, and the center of the sample was thinned by dimple grinding, followed by Ar-ion beam thinning under a low angle of 8° at 5 kV.
The sample was thinned to a final thickness of ∼100 nm and imaged using a JEOL 2010F.
This sample is thin, but the differences are revealing.
As for PMC-05, PMC-06, L-PMC-04 and L-PMC-08, just a few branches of each sample were thin but most of them were thick, resulting in their unqualified qualities.
An alternative to cryo-sectioning currently being explored is focused ion beam milling, in which material is removed from the surface of a frozen specimen by irradiation with a beam of gallium ions, until the sample is thin enough for TEM.
Obtaining detailed structural information has been hindered by the fact that all superconducting BDD samples were thin chemical-vapor-deposited films, granular [11], and polycrystals [4].
TEM samples were thin sectioned in the plane of the slice and examined on a JEOL 1200EX (Welwyn Garden City, UK).
