Predicting and designing highly gas‐sensitive semiconductors is crucial for solving growing environmental problems. Herein, four lateral heterostructures (LHSs), As6/Sb6 AC‐/ZZ‐LHSs and Sb6/Bi6 AC‐/ZZ‐LHSs, are constructed. The adsorption of NO molecule on these LHSs is investigated using first‐principle calculations. The results indicate that the adsorption of NO molecule on As6/Sb6 LHS with armchair (AC) interface is physisorption, whereas NO molecule is chemically adsorbed on As6/Sb6 LHS with zigzag (ZZ) interface and Sb6/Bi6 AC‐/ZZ‐LHSs, with strong adsorption energy and large charge transfer. All LHSs act as charge donors for the NO molecule. Meanwhile, the adsorption of NO molecule causes a significant change in the electronic properties of As6/Sb6 ZZ‐LHS and Sb6/Bi6 AC‐/ZZ‐LHSs, which shows that these LHSs have great potential for application in NO gas sensors.

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.

The band gap of the heterojunction decreases with increasing strain and becomes metallic at larger strains.

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