Abstract
has attracted great attention recently as a prospective solar cell absorber material. In this work, intrinsic defects, dopants, and their complexes in are systematically investigated by using hybrid functional theory. and are dominant native defects and pin the Fermi level near the midgap, which is consistent with the high resistivity observed experimentally. Both and introduce deep levels inside the band gap, which can trap free carriers. Our calculated deep transition levels of and are consistent well with the results of the deep-level transient spectroscopy measurement. We further study dopants (including Cu, Ti, Zn, Br, and Cl) in and find that Zn and Br/Cl are shallow acceptors and donors, respectively, which may be used to control the carrier and trap densities in . In addition, the defect complexes, i.e., and are also investigated. The interaction between the donor and acceptor defects makes the defect levels of complexes shallower and less detrimental to carrier transport.
1 More- Received 17 December 2020
- Accepted 27 April 2021
DOI:https://doi.org/10.1103/PhysRevMaterials.5.054605
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