First principles study of point defects in bulk and monolayer molybdenum disulfide

Abstract

The study of formation and diffusion of point defects in bulk and monolayer MoS2 is presented. First the formation of a split Frenkel pair was calculated. The formation energy of the split Frenkel pair in monolayer MoS2 is 5.79 eV PZ LDA (5.58 eV PBE GGA) and in bulk MoS2 is 8.43 eV PZ LDA (8.14 eV PBE GGA). The calculated diffusion barrier of a single chalcogen vacancy (V S1) in both monolayer and bulk MoS2 equals to 0.21 eV. The study of electronic properties of V S1 and I S1 in monolayer shows that both defects introduce energy states into the band gap of MoS2 monolayer. The defect levels were calculated using GVJ-2e method and equals to 1.84 eV for V S1 and 1.80 eV for I S1, from the v-band maximum.