II-IV nitrides and their alloys represent an earth-abundant and potentially cost-efficient alternative to the well-developed AlN-GaN-InN system. A major drawback with the II-IV nitrides is that ZnSnN2, the lowest band gap material, exhibits unfavorably high carrier concentrations for as-grown, stoichiometric material, limiting the material systems potential use in applications such as solar cells and light-emitting diodes. Lithium (Li) has been suggested as a shallow acceptor defect in ZnSnN2 if substituting for Zn, and hence doping with Li has been identified as a possible way to improve the electronic properties. Herein, theoretical calculations by hybrid functional density functional theory have been employed and extended to include defect complexes as well, which to this point remained unexplored. The calculations reveal that even though Li on the Zn site (the LiZn) is an acceptor, the defect may easily complex with the Lii donor, rendering the complex neutral. Our theoretical findings are supported by a Li-doping series of ZnSnN2, where a doping concentration ranging from 2.10×1019cm-3 to 1.85×1020cm-3 was obtained. The n-type carrier concentration was found to be unaffected by the doping concentration, and no systematic change in the absorption onset, probably affected by a Burstein-Moss shift, was observed. Possible group-III dopants, as have been found to yield interesting results for ZnGeN2, such as In, Ga, Al, and B, have also been investigated as an alternative dopant in ZnSnN2.
Bibliographical noteFunding Information:
This work is funded by the Research Council of Norway (RCN) and is acknowledged for the support to NEARTEAMS project, Project No. 322382; the Go-POW project, Project No. 314017; and the FME Susoltech, Project No. 257639. RCN is also acknowledged for the support to UiO MiNaLab as part of the Norwegian Micro- and Nano-Fabrication Facility, NorFab, Project No. 295864. The computations were performed on resources provided by UNINETT Sigma2, the National Infrastructure for High Performance Computing and Data Storage in Norway.
© 2022 American Physical Society.
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy (miscellaneous)