Raman tensor of zinc-phosphide (Zn₃P₂): from polarization measurements to simulation of Raman spectra

Zinc phosphide (Zn₃P₂) is a II-V compound semiconductor with promising photovoltaic and thermoelectric applications. Its complex structure is susceptible to facile defect formation, which plays a key role in further optimization of the material. Raman spectroscopy can be effectively used for defect characterization. However, the Raman tensor of Zn₃P₂, which determines the intensity of Raman peaks and anisotropy of inelastic light scattering, is still unknown. In this paper, we use angle-resolved polarization Raman measurements on stoichiometric monocrystalline Zn₃P₂ thin films to obtain the Raman tensor of Zn₃P₂. This has allowed determination of the Raman tensor elements characteristic for the A_1g, B_1g and B_2g vibrational modes. These results have been compared with the theoretically obtained Raman tensor elements and simulated Raman spectra from the lattice-dynamics calculations using first-principles force constants. Excellent agreement is found between the experimental and simulated Raman spectra of Zn₃P₂ for various polarization configurations, providing a platform for future characterization of the defects in this material.