Theoretical discovery of the phase stability, mechanical, optoelectronic, and photovoltaic properties of AZn3N3 (A = Sc, Y, La)

Abstract

In this study, the detailed first-principles calculations are employed to evaluate the structural stability, mechanical, optoelectronic, and photovoltaic properties of AZn3N3 (A = Sc, Y, La). Our calculations show that the thermodynamic, dynamical, and mechanical stability are firstly verified for the hexagonal phase with space group P63/mmc of AZn3N3. The direct band gap feature with the value of 1.7–1.8 eV is revealed for these novel compounds, and the energy gap variation is less than 100 meV. They have relatively high effective masses and exciton binding energies. Their similar absorption spectra are observed in the visible light region. Based on the spectroscopic limited maximum efficiency (SLME) model, their maximum efficiencies are about 18–20 % in the thickness of 0.5 μm. Given their optoelectronic and photovoltaic properties, ternary zinc nitrides AZn3N3 (A = Sc, Y, La) may be potential candidates for tandem solar cells.