The search for stable 2D phases of pnictogensPnictogens revealed two puckered or washboard allotropes as the most stable phases; symmetric washboard (sw)Symmetric Washboard (sw) and asymmetric washboard (aw) structuresAsymmetric washboard (aw) structure; and a hexagonal buckled (hb)Hexagonal buckled (hb) allotrope. The buckled structure has flatter zigzag folds compared with the puckered structures that are characterized by deeper armchair ridges. The stable monolayers are generally named with suffix ‘ene’, although the structure contains no double bondsDouble bonds, e.g., nitrogeneNitrogene, phosphorenePhosphorene, arseneneArsene, antimoneneAntimonene, and bismutheneBismuthene. The five valence electronsValence electrons in the outer shell (ns2p3) allow the formation of sp2-like orbitals, with the remaining orbital in each atom containing a lone electron pairLone electron pair that influences the final structure and physicochemical behavior. The diverse structures have similar cohesive energies and energetic stability. Therefore, the most stable bonding configuration changes with the group element. Essentially, all the monolayers possess energetic, dynamic, and thermal stabilityThermal stability as free-standing 2D lattices. The wide-gap semiconductors of this group exhibit both direct and indirect band gaps and cover a broad range of energies. The electronic properties, such as the band gap, are tunable by strain engineeringStrain engineering and by increasing the number of layers in few-layer assemblies. The synthesisSynthesis of the individual monolayers is at dissimilar stages. While nitrogeneNitrogene could not be prepared yet, quasi-free weakly bonded adsorbed monolayers and sheets with few layers exist for the other group members. The high carrier mobilityCarrier mobility and band gap tunability provide numerous opportunities for practical application. In few-layer systems, some compounds are topological semimetalsSemimetals with the possibility of realizing Dirac conesDirac cone and topological insulators. Based on their large carrier mobility, wide and tunable band gap, and low thermal conductivity, these 2D materials qualify for applications in electronics, e.g., as field-effect transistors; in optoelectronicsOptoelectronics, e.g., as photodetectorsPhotodetector; and as light emitting devices. Other potential applications include batteries, photovoltaicsPhotovoltaics, spintronicsSpintronics, thermoelectrics, nonlinear optics, catalysis, biosensors, and gas sensorsGas sensor.

Elemental Group–VA Monolayers

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发表日期：

2025年

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Peter Hess

摘要

The search for stable 2D phases of pnictogensPnictogens revealed two puckered or washboard allotropes as the most stable phases; symmetric washboard (sw)Symmetric Washboard (sw) and asymmetric washboard (aw) structuresAsymmetric washboard (aw) structure; and a hexagonal buckled (hb)Hexagonal buckled (hb) allotrope. The buckled structure has flatter zigzag folds compared with the puckered structures that are characterized by deeper armchair ridges. The stable monolayers are generally named with suffix ‘ene’, although the structure contains no double bondsDouble bonds, e.g., nitrogeneNitrogene, phosphorenePhosphorene, arseneneArsene, antimoneneAntimonene, and bismutheneBismuthene. The five valence electronsValence electrons in the outer shell (ns2p3) allow the formation of sp2-like orbitals, with the remaining orbital in each atom containing a lone electron pairLone electron pair that influences the final structure and physicochemical behavior. The diverse structures have similar cohesive energies and energetic stability. Therefore, the most stable bonding configuration changes with the group element. Essentially, all the monolayers possess energetic, dynamic, and thermal stabilityThermal stability as free-standing 2D lattices. The wide-gap semiconductors of this group exhibit both direct and indirect band gaps and cover a broad range of energies. The electronic properties, such as the band gap, are tunable by strain engineeringStrain engineering and by increasing the number of layers in few-layer assemblies. The synthesisSynthesis of the individual monolayers is at dissimilar stages. While nitrogeneNitrogene could not be prepared yet, quasi-free weakly bonded adsorbed monolayers and sheets with few layers exist for the other group members. The high carrier mobilityCarrier mobility and band gap tunability provide numerous opportunities for practical application. In few-layer systems, some compounds are topological semimetalsSemimetals with the possibility of realizing Dirac conesDirac cone and topological insulators. Based on their large carrier mobility, wide and tunable band gap, and low thermal conductivity, these 2D materials qualify for applications in electronics, e.g., as field-effect transistors; in optoelectronicsOptoelectronics, e.g., as photodetectorsPhotodetector; and as light emitting devices. Other potential applications include batteries, photovoltaicsPhotovoltaics, spintronicsSpintronics, thermoelectrics, nonlinear optics, catalysis, biosensors, and gas sensorsGas sensor.