First-principles study of the structural, electronic and optical properties of Zn1-xHgxSe (x=0, 0.25, 0.50, 0.75, 1)

The structural, electronic and optical properties of Zn1-xHgxSe alloys with different Hg concentrations (x = 0, 0.25, 0.50, 0.75, 1) are studied through first-principles calculations. The stability of three Zn1-xHgxSe ternary alloys is proved by calculating phonon spectrum. It is found that the SOC effect on the band gap is less than 0.2 eV. In addition, the HSE06 functional underestimates the band gap of ZnSe, so the PBE0 functional is employed to calculate the electronic and optical properties of Zn1-xHgxSe alloys. The tunable band gap can be realized by Hg doping from 2.5 to 0 eV Zn0.75Hg0.25Se and Zn0.50Hg0.50Se have suitable band gaps (1.0-1.8 eV) for solar cells. Zn0.50Hg0.50Se shows wider and higher absorption coefficient than that of Zn0.75Hg0.25Se in the visible light range.

Automated summary

The structural, electronic and optical properties of Zn1-xHgxSe alloys with different Hg concentrations were studied. It was found that Hg doping can tune the band gap, providing suitable band gaps and higher absorption coefficients for solar cells.