Structures, mobilities, electronic and optical properties of two-dimensional α-phase group-VI binary compounds: α-Se2Te and α-SeTe2

Abstract

Based on the first-principles calculations, we confirm the geometry and electronic structures of two binary group-VI compounds: monolayer α-Se2Te and α-SeTe2. The stabilities are confirmed by the cohesive energies, phonon dispersions, and elastic constants. The mechanical properties, strain-stress relationships, and strain-dependent variations of band gaps and band structures are investigated detailed. Furthermore, the high carrier mobilities (up to 5.4×103 cm2V−1s−1) and optical absorption coefficients (several 105 cm−1) are also exhibited, demonstrating the great application potentials in optoelectronics.