Effect of strain profiling on anisotropic opto-electronic properties of As2X3 (X =S, Te) monolayers from first principles

Strain Engineering is a widely adopted approach to modulate the opto-electronic performance of 2-Dimensional (2D) materials. Recently, anisotropic Van der Waals (vdW) based 2D As 2 S 3 monolayer has gained significant attention within the scientific community due to its stability in ambient conditions. Similar compounds like As 2 Te 3 have also been theoretically explored. However, its indirect bandgap nature limits its application in optical devices. In this study, a systematic study of compressive and tensile strain on three profiles–Uniaxial along a-axis, Uniaxial along b-axis and biaxial strain from −10% to +10%, is performed for As 2 S 3 and As 2 Te 3 monolayers. Certain strain profiles like Uniaxial tensile strain of 8% along b-axis results in transition to direct bandgap material. Similarly, for As 2 Te 3 , shear strain of (−10%, +8%) along (a, b) axis results in direct bandgap material. In addition, the anisotropic optical absorption spectrum is obtained for unstrained and strained monolayers within the random phase approximation (RPA).