Jibran Muhammad, Sun Xia, Wang Bing, Yamauchi Yasushi, Ding Zejun
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics, University of Science and Technology of China 96 Jinzhai Road Hefei Anhui 230026 China
National Institute for Materials Science 1-2-1 Sengen Tsukuba Ibaraki 305-0047 Japan.
RSC Adv. 2019 Sep 9;9(48):28234-28240. doi: 10.1039/c9ra06236j. eCollection 2019 Sep 3.
The electronic structure and optical properties of group-VA (N, P, As, and Sb)-doped CuZnSiSe alloys have been studied using a hybrid functional through density functional theory calculations. The minor lattice distortion and small formation energy indicate that synthesis of these alloys is highly possible in experiment. For each doped alloy, an isolated and partially filled intermediate band (IB) appears in its band structure. The doping-induced IB is mainly contributed by the s states of the doped group-VA atom and the p states of four neighboring Se atoms, and slightly by the d states of eight Cu atoms. The existence of an IB obviously enhances the absorption coefficient with two additional absorption peaks in the visible light range. For P, As and Sb-doped CuZnSiSe alloys, not only the bandgap between the valence band maximum and the conduction band minimum but also the sub bandgap between the valence band maximum and the IB are very close to the optimal values for visible light absorption. Therefore, these alloys are recommended as good candidates for IB solar cell materials.
