Abstract
Formation energies of possible vacancies under different oxygen partial pressures were studied using an
ab initio
density functional theory and supercell approach. Under oxygen-rich conditions, lead vacancies are the stable ones throughout the band gap, and their ionization level locates at
0.56
eV
from the top of valence band, which may contribute to
p
-type conduction. Under oxygen-poor conditions, oxygen vacancies are the stable ones at the top of the valence band. It is a deep donor that may not only dilute the acceptor carriers to weaken the
p
-type conduction but hardly contribute to
n
-type conduction.