Stability of Cd1-xZnxOyS1-yQuaternary Alloys Assessed with First-Principles Calculations.
One route to decreasing the absorption in CdS buffer layers in Cu(In,Ga)Se2and Cu2ZnSn(S,Se)4thin-film photovoltaics is by alloying. Here we use first-principles calculations based on hybrid functionals to assess the energetics and stability of quaternary Cd, Zn, O, and S (Cd1-xZnxOyS1-y) alloys within a regular solution model. Our results identify that full miscibility of most Cd1-xZnxOyS1-ycompositions and even binaries like Zn(O,S) is outside typical photovoltaic processing conditions. The results suggest that the tendency for phase separation of the oxysulfides may drive the nucleation of other phases such as sulfates that have been increasingly observed in oxygenated CdS and ZnS.
Materials Science Division, Lawrence Livermore National Laboratory , Livermore, California 94550, United States.
Joel B
http://orcid.org/0000-0002-5384-5248
JB
Varley
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
Xiaoqing
http://orcid.org/0000-0001-6058-9732
X
He
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
Angus
A
Rockett
Materials Science Division, Lawrence Livermore National Laboratory , Livermore, California 94550, United States.
Vincenzo
http://orcid.org/0000-0003-2415-4656
V
Lordi
CIGS; CZTS; alloy; buffer layer; density functional theory; thin-film photovoltaics