Abstract
Surface treatments of Cu2ZnSnS4 have shown a beneficial effect on the solar cells performance due to a reduction in the open‐circuit voltage (VOC) deficit. Several reasons have been suggested for the VOC deficit, including an unfavorable band alignment at the buffer/Cu2ZnSnS4 interface. Herein, the influence of Cu2ZnSnS4 surface treatment (air exposure and air anneal) on the electronic and chemical properties of Cu2ZnSnS4 and CdS/Cu2ZnSnS4 interfaces is investigated. Using hard X‐ray photoelectron spectroscopy, it is shown that the band alignment at the CdS/Cu2ZnSnS4 interface is not significantly altered by the applied surface treatment. The device enhancement is instead connected to interface passivation for the surface‐treated Cu2ZnSnS4 samples due to the formation of SnOx, which is shown to not be fully removed upon KCN etching prior to the buffer layer deposition. In addition, a surface treatment of the Cu2ZnSnS4 absorber prior to buffer layer deposition influences the growth of CdS buffer, as a thicker CdS‐overlayer is observed to grow on a surface‐treated Cu2ZnSnS4 sample as compared with a nontreated sample. This suggests that a reoptimization of the CdS thickness for a given Cu2ZnSnS4 surface treatment is required.
Highlights
Surface treatments of Cu2ZnSnS4 have shown a beneficial effect on the solar cells performance due to a reduction in the open-circuit voltage (VOC) deficit
To obtain information on the chemical properties of a treated CZTS surface, Al Kα X-ray photoelectron spectroscopy (XPS) measurements were carried out on an AA sample, which has been etched in KCN solution, and the results are compared with a nontreated (F) CZTS sample that has been etched in KCN
Several effects of an air anneal treatment of kesterite solar cells prior to buffer layer deposition have been described in the literature where the formation of SnOx has often been reported as a result of oxygen incorporation into the absorber
Summary
Surface treatments of Cu2ZnSnS4 have shown a beneficial effect on the solar cells performance due to a reduction in the open-circuit voltage (VOC) deficit. The influence of Cu2ZnSnS4 surface treatment (air exposure and air anneal) on the electronic and chemical properties of Cu2ZnSnS4 and CdS/Cu2ZnSnS4 interfaces is investigated. The efficiency is still far below the theoretical limit and below that of other types of solar cells containing less abundant and toxic elements.[1] It is well known that the performance of kesterite thin-film solar cells depends hard X-ray photoelectron spectroscopy, it is shown that the band alignment at the strongly on the atomic structure and chem-. CdS-overlayer is observed to grow on a surface-treated Cu2ZnSnS4 sample as compared with a nontreated sample. This suggests that a reoptimization of the CdS thickness for a given Cu2ZnSnS4 surface treatment is required. Introduction information on the structural, chemical, and electronic properties on different depths and of buried interfaces of a thin-film
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
