Electronic properties of both Pb and S vacancy defect in PbS(-100) have been studied using the first principles density
functional theory (DFT) calculations with the plane-wave pseudopotentials. The densities of states are computed to
investigate the effect of the Pb and S vacancy on the electronic structure, respectively. In the case of S vacancy defect,
the Fermi energy shifted to the conduction band making it an n-type PbS (donor). While in the case of Pb vacancy the
DOS do change appreciably.