Excellent carrier mobility and opto/electronics performance material prediction: Focusing on single layer X2Te3 (X = Sb, Bi)

Low-dimensional materials cleaved from their high performance topological-insulators-property bulk counterparts are attractive to be investigated. Here, the researched X₂Te₃ (X = Sb, Bi) single layer materials and their thermodynamical stabilities are proved through our calculations. The indirect band gaps pulse with the high carrier mobilities are also discussed based on first-principle calculations. On basis of the calculation, the low cleavage energies are about 0.34 J m⁻² that is comparable with that of graphite, which imply a high possibility to obtain the single layer from exfoliating bulk counterpart. Band gaps are simulated as between 0.65 and 1.31 eV using different functionals, moreover, the band structures with and without SOC effect are all considered. The SOC effect results certify that X₂Te₃ monolayers are different from their bulk counterparts, they are not topological insulators. The largest electron mobility selected in their impressive carrier mobilites is 27.91×10³ cm²V⁻¹S⁻¹ that bears comparison to that of silicene. Moreover, the mechanical properties include Young's moduli and Poisson's ratio are studied too. Meanwhile, the biaxial strain can effectively modify the band gaps. Finally, outstanding visible and near-infrared light absorption abilities mainly from ~400 to around 1400 nm may guide single layer X₂Te₃ to a promises applications in photovoltaics.