First principles calculations for band-gap energy properties of non-polar and semi-polar ternary nitride alloys under in-plane strain

Strain-induced band-gap energies properties of non-polar and semi-polar ternary nitride alloys are investigated by first-principles calculation based on density functional theory. The tensile and compressive strains in non-polar and semi-polar plane of wurtzite structures are analyzed and discussed. From the calculation results, we find that the band-gap energies of both Al0.5Ga0.5N and In0.5Ga0.5N super-cells under strains in m-plane (1100) are smaller than that in a-plane (1120). In addition, m-plane (1100) Al0.5Ga0.5N based optoelectronic device will have more significant shift of emission wavelength than a-plane (1120) and semi-polar plane (1122) with the same strains. The tensile and compressive strains in semi-polar plane have similar magnitude of influence on the emission wavelength of In0.5Ga0.5N. The calculations provide a qualitative picture of the strain effects on the band-gap energy.