Abstract :
Structural transitions in amorphous red phosphorus were studied at ambient temperature and pressures up to 12 GPa. Amorphous (red) phosphorus was observed to transform into crystalline black phosphorus at 7.5 ± 0.5 GPa using diamond anvil cell Raman spectroscopy, x-ray diffraction and a direct equation of state (EoS) measurement. The transition was found to be irreversible and the material recovered upon pressure cycling to 10 to 12 GPa was crystalline orthorhombic black phosphorus. A third order Birch–Murnaghan EoS was fit to the data and a bulk modulus (B0) of 11.2 GPa was measured for amorphous red phosphorus.
