Search

Isotopically pure 13C homoepitaxial diamond layer of 20±5 microns thickness was grown on top of a brilliant cut diamond anvil by a microwave plasma chemical vapor deposition process for application as a stress sensor. This isotopically pure diamond tip was then used in conjunction with a natural abundance 12C diamond anvil to generate high pressure on a soft sample containing carbon nanotubes to 100 GPa. The 13C diamond Raman signal remained a distinct single peak showing that the mean normal stress experienced by this thin layer is uniform to the highest pressure. The stress-induced shift of the 13C layer is related to the quasihydrostatic pressure in the sample chamber using a ruby pressure sensor and shows a remarkably linear behavior to extreme pressures. [ABSTRACT FROM AUTHOR]