Temperature and pressure dependence of the fluorescence spectrum of high-pressure synthetic corundum-type Ga2O3:Cr3+, structural stability, and crystal growth under high pressure

Abstract

The pressure dependence of the R1 and R2 peaks of the fluorescence spectra of high-pressure-synthesized corundum-type Ga2O3:Cr3+ was measured up to 50 GPa using a diamond anvil cell pressurized at room temperature in an argon medium. The temperature dependence of the R1 and R2 peaks was measured at low temperatures under ambient pressure from 303 to 83 K. From the measurement results, the pressure scale and low-temperature scale were determined using R1 and R2. X-ray diffraction experiments at high pressure, which were performed to confirm the effective range of the pressure scale, showed that the corundum structure undergoes a phase transition to a Rh2O3(II)-type structure at 54–65 GPa; this pressure scale is, thus, valid up to approximately 50 GPa. We also investigated the crystal growth time to optimize the crystal size of Ga2O3:Cr3+ for diamond anvil cell experiments.