The formation conditions, structure, and properties of the recently discovered phosphide, Si12P5 (initially assigned Si7P3), have been studied using x-ray diffraction, high-resolution transmission electron microscopy, photospectrometry, and a four-point probe. The phosphide formed in amorphous Si–P alloy thin films with 30, 35 and 44 at. % P after annealing at 1000 °C for 30 min. During annealing at 1100 °C, the phosphide dissociated through P evaporation. The Si12P5 phase is proposed to have rhombohedral symmetry with a P3̄1m space group and a C5W12 structure. The hexagonal lattice parameters measured were a=6.16±0.05 Å and c=13.17±0.01 Å. The optical band gap and the electrical resistivity of the phosphide were determined to be 1.55 eV and 5 mΩ cm, respectively. The Gibbs free energy diagram for the Si–P system was modified to include this new Si12P5 phase.

This content is only available via PDF.
You do not currently have access to this content.