Transparent graphitic tiles synthesized from carbon nanowalls by shock compression and rapid quenching

Abstract

Here, we report the synthesis of transparent graphitic tiles from carbon nanowalls (CNWs) by shock compression and rapid quenching. The transparent tiles are included in samples recovered from shock pressures above 57 GPa. They exhibit strong photoluminescence but no diamond Raman peak, similar to the case of amorphous diamond synthesized from C60 fullerene and neutron-irradiated graphite. However, the electron energy-loss spectroscopy exhibits relatively intense π* peak associated with graphite, that is inconsistent with the transparency. From these results, it is suggested that the transparent tile is a mixture of amorphous diamond and superhard graphitic material with the transparency. Such carbon phase may come from the unique structural feature of CNWs as the starting material for the shock compression.