Charged vacancy defects in monolayer phosphorene

Abstract

Two-dimensional semiconductor phosphorene has attracted extensive research interests for potential applications in optoelectronics, spintronics, catalysis, sensors, and energy conversion. To harness phosphorene's potential requires a better understanding of how intrinsic defects control carrier concentration, character, and mobility. Using density functional theory and a charge correction scheme to account for the appropriate boundary conditions, we conduct a comprehensive study of the effect of structure on the formation energy, electronic structure, and charge transition level of the charged vacancy point defects in phosphorene. We predict that the neutral vacancy exhibits a 9-5 ring structure with a formation energy of 1.7 eV and transitions to a negatively charged state at a Fermi level 1.04 eV above the valence band maximum. The corresponding optical charge transitions display sizable Frank-Condon shifts with a large Stokes shift of 0.3 eV. Phosphorene vacancies should become negatively charged in n-doped phosphorene, which would passivate the dopants and reduce the charge carrier concentration and mobility.

Sulfur Vacancy Related Optical Transitions in Graded Alloys of MoxW1‐xS2 Monolayers

“…While a few studies have used spin‐orbit coupling for WS 2 and MoS 2 monolayers, there are not many studies involving the spin‐orbit coupling effect with the V S defect. When the V S defect is considered, calculations reveal that the valence band splitting tends to decrease to 0.05 and 0.30 eV for both MoS 2 [ 59,60 ] , and WS 2 [ 61 ] respectively. STM imaging of the V S defect has confirmed the valence band splitting for WS 2 to be 0.25 eV [ 61 ] while only theoretical calculations have been shown to yield a decrease in valence band splitting for MoS 2 with the V S defect.…”

Diffusion and Coalescence of Phosphorene Monovacancies Studied Using High-Dimensional Neural Network Potentials

“…According to our DFT calculations, the SV(5|9) defect has a formation energy of 1.65 eV and a total magnetic moment of 1 μ Bm , in good agreement with previous results. 18 , 23 , 28 , 50 − 54 The magnetism arises from a dangling bond atom, which forms only two bonds instead of three. Consequently, there is an unpaired electron, mainly localized in the vicinity of the broken bond (see Figure 2 ).…”

Identification and Manipulation of Defects in Black Phosphorus

“…Note that Sn is used in the synthesis procedure; its presence is confirmed by X-ray photoemission spectroscopy (Figure S5 of the Supporting Information). We note that, though there have been previous DFT calculations on different types of BP defects, ,,− only 5656-MV-1 and Sn-1 configurations have been previously considered as candidates to explain dumbbell features seen in STM experiments. ,,, …”