How much gallium do we need for a p-type Cu(In,Ga)Se2?

Doping in the chalcopyrite Cu(In,Ga)Se2 is determined by intrinsic point defects. In the ternary CuInSe2, both N-type conductivity and P-type conductivity can be obtained depending on the growth conditions and stoichiometry: N-type is obtained when grown Cu-poor, Se-poor, and alkali-free. CuGaSe2, o...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:APL materials 2022-06, Vol.10 (6), p.061108-061108-7
Hauptverfasser: Ramírez, Omar, Lanzoni, Evandro Martin, Poeira, Ricardo G., Weiss, Thomas P., Leturcq, Renaud, Redinger, Alex, Siebentritt, Susanne
Format: Artikel
Sprache:eng
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Doping in the chalcopyrite Cu(In,Ga)Se2 is determined by intrinsic point defects. In the ternary CuInSe2, both N-type conductivity and P-type conductivity can be obtained depending on the growth conditions and stoichiometry: N-type is obtained when grown Cu-poor, Se-poor, and alkali-free. CuGaSe2, on the other hand, is found to be always a P-type semiconductor that seems to resist all kinds of N-type doping, no matter whether it comes from native defects or extrinsic impurities. In this work, we study the N-to-P transition in Cu-poor Cu(In,Ga)Se2 single crystals in dependence of the gallium content. Our results show that Cu(In,Ga)Se2 can still be grown as an N-type semiconductor until the gallium content reaches the critical concentration of 15%–19%, where the N-to-P transition occurs. Furthermore, trends in the Seebeck coefficient and activation energies extracted from temperature-dependent conductivity measurements demonstrate that the carrier concentration drops by around two orders of magnitude near the transition concentration. Our proposed model explains the N-to-P transition based on the differences in formation energies of donor and acceptor defects caused by the addition of gallium.
ISSN:2166-532X
2166-532X
DOI:10.1063/5.0091676