Fig. 6: Differences in the formation energy (ΔEf) as functions of biaxial strain ϵ(%) for substitutional defects in graphene, MoSe2 and phosphorene.
From: Strain-modulated defect engineering of two-dimensional materials

As evident from the figure, for all materials Ef increases with strain when the atomic radius of the impurity atoms is smaller than that of the host atom, and the trend is the opposite when the impurity atom is larger than the host atom.