Healing detrimental defects in two-dimensional semiconductors through strain engineering

Abstract

Defects are unavoidable in two-dimensional (2D) semiconductors, which might cause adverse effects on their optoelectronic properties. The strain engineering could be an effective way to heal these detrimental defects since the strain induced energy shift between defect levels and band edges could be significantly dissimilar. Using a large-scale time-dependent density functional theory method, we study the strain dependence of the band gap and optical gap in the pristine and defective fluorographene. The defect states within the band gap could be effectively eliminated by applying the biaxial tension strain, which recover the band gap and optical gap of the perfect fluorographene. The strain dependence of the optical gap in the defective fluorographene significantly differ from that in the perfect material, that can be verified by further experimental measurements. The computational procedures are readily applied to other 2D materials for future strain engineering to heal the detrimental defects.