Theoretical optoelectronic analysis of intermediate-band photovoltaic material based on ZnY_1−xO_x (Y = S, Se, Te) semiconductors by first-principles calculations

Author： Kong-Ping Wu Shu-Lin Gu Jian-Dong Ye Kun Tang Shun-Ming Zhu Meng-Ran Zhou You-Rui Huang Rong Zhang You-Dou Zheng

Publisher： IOP Publishing

E-ISSN： 1741-4199|22|10|107103-107108

ISSN： 1674-1056

Source： Chinese Physics B, Vol.22, Iss.10, 2013-10, pp. : 107103-107108

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Abstract

The structural, energetic, and electronic properties of lattice highly mismatched ZnY_1−xO_x (Y = S, Se, Te) ternary alloys with dilute O concentrations are calculated from first principles within the density functional theory. We demonstrate the formation of an isolated intermediate electronic band structure through diluted O-substitute in zinc-blende ZnY (Y = S, Se, Te) at octahedral sites in a semiconductor by the calculations of density of states (DOS), leading to a significant absorption below the band gap of the parent semiconductor and an enhancement of the optical absorption in the whole energy range of the solar spectrum. It is found that the intermediate band states should be described as a result of the coupling between impurity O 2p states with the conduction band states. Moreover, the intermediate bands (IBs) in ZnTeO show high stabilization with the change of O concentration resulting from the largest electronegativity difference between O and Te compared with in the other ZnSO and ZnSeO.