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arXiv 2201.00116cond-mat.mtrl-sci
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可调屈曲引起的BN单分子膜紫外吸收增强

Enhanced ultraviolet absorption in BN monolayers caused by tunable buckling

Nzar Rauf Abdullah, Botan Jawdat Abdullah, Chi-Shung Tang, Vidar Gudmundsson

摘要:

研究了六方氮化硼(BN)单层膜在紫外光谱范围内的光学性质。通过增加平面屈曲,可以将平坦BN单层的通过sp $^2$杂化的强$σ\text{-}σ$键改变为通过sp $^3$杂化的更强的$σ\text{-}π$键。这引起了$s$-和$p$-轨道贡献,以在费米能周围形成态密度,并且这些态在存在增加的平面屈曲时位错到较低的能量。因此,平坦BN单层的宽带隙减小到屈曲BN单层中的较小带隙,从而增强其在深UV区域中的光学活性。研究了薄膜的介电函数、反射率、吸收率和电导率谱等光学性质。结果表明,吸收率可以提高$(12\text{-}15)\%$的中间值的平面屈曲在深紫外区,和$(15\text{-}20)\%$在较高的值的平面屈曲在近紫外区。此外,光学传导性通过在可见光和深UV区域中增加的平面屈曲来增强,这取决于入射光的偏振方向。我们的研究结果可能是有用的光电子BN单层器件在紫外范围内,包括紫外光谱,深紫外通信,紫外光探测器。

英文摘要:

The optical properties of a hexagonal Boron Nitride (BN) monolayer across the UV spectrum are studied by tuning its planar buckling. The strong $σ\text{-}σ$ bond through sp$^2$ hybridization of a flat BN monolayer can be changed to a stronger $σ\text{-}π$ bond through sp$^3$ hybridization by increasing the planar buckling. This gives rise to the $s$- and $p$-orbital contributions to form a density of states around the Fermi energy, and these states dislocate to a lower energy in the presence of an increased planar buckling. Consequently, the wide band gap of a flat BN monolayer is reduced to a smaller band gap in a buckled BN monolayer enhancing its optical activity in the Deep-UV region. The optical properties such as the dielectric function, the reflectivity, the absorption, and the optical conductivity spectra are investigated. It is shown that the absorption rate can be enhanced by $(12\text{-}15)\%$ for intermediate values of planar buckling in the Deep-UV region, and $(15\text{-}20)\%$ at higher values of planar buckling in the near-UV region. Furthermore, the optical conductivity is enhanced by increased planar buckling in both the visible and the Deep-UV regions depending on the direction of the polarization of the incoming light. Our results may be useful for optoelectronic BN monolayer devices in the UV range including UV spectroscopy, deep-UV communications, and UV photodetectors.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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