In situ high-pressure spectroscopic studies using moissanite (4H-SiC) anvils

We examined the Raman scattering and IR absorption spectroscopy of 4H-SiC and its performance as an anvil material for high-pressure UV-visible absorption spectroscopic measurements. The first- and second-order Raman peaks of 4H-SiC and diamond do not coincide. 4H-SiC does not have obvious signals from 2330-5000 cm-1, suggesting that 4H-SiC anvils are beneficial for high-pressure studies of samples whose Raman signals locate in the region of diamond. Above 1800 cm-1, the transmitted signal of 4H-SiC in the IR absorption spectra, measured through 4.6 mm thickness is much higher than that of type IIa diamond. An in situ high-pressure UV-visible absorption spectroscopy study on CdI2 was carried out up to 28.0 GPa using 4H-SiC anvil cells (4H-SAC) with a 400 μm culet and the acquired band gap narrowed with increasing pressure. These results show that 4H-SiC has an excellent performance in high-pressure spectroscopic studies.