Benzene-like N6 rings in a Be2N6 monolayer: a stable 2D semiconductor with high carrier mobility,Journal of Materials Chemistry C

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Benzene-like N6 rings in a Be2N6 monolayer: a stable 2D semiconductor with high carrier mobility
Journal of Materials Chemistry C ( IF 5.7 ) Pub Date : 2017-10-03 00:00:00 , DOI: 10.1039/c7tc03363j
Feng Li _{1,

2,

3,

4,

5} , Yu Wang _{1,

2,

3,

4,

5} , Hong Wu _{6,

7,

8,

9,

10} , Zhifa Liu _{6,

7,

8,

9} , Urs Aeberhard _{6,

7,

8,

9} , Yafei Li _{1,

2,

3,

4,

5}

Affiliation

Designing new two-dimensional (2D) semiconductors with high carrier mobilities is highly desirable for material innovation, especially when the configuration has novel topological properties. Here, we proposed a first-principles-based design of a 2D crystal, namely a Be₂N₆ monolayer. In which, each N atom is shared by two neighboring N atoms and one Be atom, forming a novel moiety of benzene-like N₆ rings. Rather than the instability of hexazine, the Be₂N₆ monolayer has a moderate cohesive energy, good kinetic and thermodynamic stability, due to the stabilization effect of the Be element by forming twelve classical two-centre–two-electron (2c–2e) σ-bonds and five multicenter 6c–2e π-bonds. There are ten π electrons in a unit cell, which satisfies the Hückel rule [4n + 2] (n = 2), indicating the Be₂N₆ monolayer aromaticity. As a result, the Be₂N₆ monolayer has an ultra-high mechanical strength of up to 200 J m⁻². Particle-swarm optimization (PSO) computations reveal that a cyclo-N₆-containing Be₂N₆ monolayer is the lowest-energy configuration in 2D forms with a stoichiometry of 1 : 3, and therefore could be synthesized experimentally. Furthermore, the Be₂N₆ monolayer is an indirect semiconductor with a band gap of 1.71 eV at the hybrid functional level, close to that of the bulk amorphous silicon ∼1.6 eV widely used in solar cells. At this point, the high electron mobility of up to ∼10⁴ cm² V⁻¹ s⁻¹ and visible-light absorption of ∼10⁵ cm⁻¹ are observed for the Be₂N₆ monolayer. If realized, it will not only enrich the knowledge of the bonding nature of nitrogen but could also have potential applications in electronics and optoelectronics.

中文翻译：

Be ₂ N ₆单层中的类苯N ₆环：具有高载流子迁移率的稳定2D半导体

设计高载流子迁移率的新型二维（2D）半导体对于材料创新非常必要，尤其是当该配置具有新颖的拓扑特性时。在这里，我们提出了一种基于第一原理的二维晶体设计，即Be ₂ N ₆单层。其中，每个N原子被两个相邻的N原子和一个Be原子共享，形成了类似苯的N ₆环的新部分。Be ₂ N ₆而不是hexazine的不稳定性由于Be元素通过形成十二个经典的两中心–两电子（2c–2e）σ键和五个多中心的6c–2eπ键的稳定作用，单层具有适度的内聚能，良好的动力学和热力学稳定性。。晶胞中有十个π电子，满足Hückel规则[4 n + 2]（n = 2），表明Be ₂ N ₆单层芳香。结果，Be ₂ N ₆单层具有高达200 J m ^-2的超高机械强度。粒子群优化（PSO）计算表明，含环N ₆的Be ₂ N ₆单层是2D形式的最低能量构型，化学计量比为1：3，因此可以通过实验合成。此外，Be ₂ N ₆单层是一种间接半导体，在杂合功能水平上的带隙为1.71 eV，接近太阳能电池中广泛使用的约1.6 eV的块状非晶硅。此时，对于Be ₂ N _6，观察到高达〜10 ⁴ cm ² V ^-1 s ^-1的高电子迁移率和〜10 ⁵ cm ^-1的可见光吸收。单层。如果实现，它将不仅丰富关于氮键合性质的知识，而且在电子和光电子领域也有潜在的应用。

更新日期：2017-11-16

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