Local Bonding Influence on the Band Edge and Band Gap Formation in Quaternary Chalcopyrites.

ABSTRACT: Quaternary chalcopyrites have shown to exhibit tunable band gaps with changing anion composition. Inspired by these observations, the underlying structural and electronic considerations are investigated using a combination of experimentally obtained structural data, molecular orbital considerations, and density functional theory. Within the solid solution Cu₂ZnGeS_4-x Se _x , the anion bond alteration parameter changes, showing larger bond lengths for metal-selenium than for metal-sulfur bonds. The changing bonding interaction directly influences the valence and conduction band edges, which result from antibonding Cu-anion and Ge-anion interactions, respectively. The knowledge of the underlying bonding interactions at the band edges can help design properties of these quaternary chalcopyrites for photovoltaic and thermoelectric applications.

SUBMITTER: Miglio A 

PROVIDER: S-EPMC5604395 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature