Details

Autor(en) / Beteiligte

• Yuan, Zhenkun
• Xiong, Yihuang
• Hautier, Geoffroy

Titel

First-principles study of intrinsic and hydrogen point defects in the earth-abundant photovoltaic absorber ZnP

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2023-10, Vol.11 (38), p.2592-26

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Zinc phosphide (Zn 3 P 2 ) has had a long history of scientific interest largely because of its potential for earth-abundant photovoltaics. To realize high-efficiency Zn 3 P 2 solar cells, it is critical to understand and control point defects in this material. Using hybrid functional calculations, we assess the energetics and electronic behavior of intrinsic point defects and hydrogen impurities in Zn 3 P 2 . All intrinsic defects are found to act as compensating centers in p-type Zn 3 P 2 and have deep levels in the band gap, except for zinc vacancies which are shallow acceptors and can act as a source of doping. Our work highlights that zinc vacancies rather than phosphorus interstitials are likely to be the main source of p-type doping in as-grown Zn 3 P 2 . We also show that Zn-poor and P-rich growth conditions, which are usually used for enhancing p-type conductivity of Zn 3 P 2 , will facilitate the formation of certain deep-level defects (P Zn and P i ) which might be detrimental to solar cell efficiency. For hydrogen impurities, which are frequently present in the growth environment of Zn 3 P 2 , we study interstitial hydrogen and hydrogen complexes with vacancies. The results suggest small but beneficial effects of hydrogen on the electrical properties of Zn 3 P 2 . The shallow V Zn acceptors are proposed as the source for p-type doping in the Zn 3 P 2 solar absorber. Not only V Zn but also deep-level defects P Zn and P i have increased concentrations in non-stoichiometric, P-rich Zn 3 P 2 .