First principles studies on infrared band structure and absorption of As/Sb lateral heterostructures

Two-dimensional materials have been extensively investigated for fabricating high-performance visible optoelectronic devices. Considering the significance of mid-infrared band, narrow-band two-dimensional semiconductor materials have become the key point. In this work, we bring out two kinds of monolayer lateral heterostructures (LHSs) based on arsenic (As)/antimony (Sb) to realize the narrow band structure. The bandgap of LHS with an armchair interface is calculated to be 1.1 eV with an indirect band through the first principle, and the bandgap of LHS with a zigzag interface is 0.57 eV with a direct band. Their bandgaps are all shrunk by applying tensile or compressive strains. Furthermore, indirect-to-direct transitions appear in the armchair LHS when tensile strains are applied. Partial density-of-states and charge density distributions indicate that electron transmission from Sb atoms to As atoms may be the main factor for the reduction of the bandgap. In addition, the tensile strain extends the optical absorption to the infrared region. The As/Sb lateral heterostructures proposed in this paper are of great significance for infrared optoelectronic devices.