Abstract Using first-principles density functional theory calculations, we investigate the structural and electronic properties of layer number (n) dependent two-dimensional (2D) atomically thick (100) diamond nanofilms related to surface functionalization of hydrogen and fluorine. The nanofilms with functionalized surface are dynamically and thermally stable demonstrated by phonon dispersion curves and ab initio molecular dynamics simulations. The band gaps of semi-functionalized nanofilms are in the region of 2.41–2.65 eV almost unchanged related to n or surface functionalization, contributed by the electronic feature of the unfunctionalized side. For the cases of full-functionalization on both sides of the nanofilms, the band gaps are larger than that for the semi-functionalized 2D nanofilms. These band gaps decrease following a nonlinear inverse law of n, attributed to a quantum confinement effect. The fluorine-functionalized nanofilms present the larger band gaps with respect to the cases of hydrogen-functionalization. Moreover, the absorption spectra of these 2D nanofilms show an absorption edge at around 2.8 eV for semi-functionalized and upon 4.8 eV for full-functionalized nanofilms. Based on the theoretical results, the proposed nanofilms can inspire more efforts in practical applications and fabricating low-dimensional diamond-based optoelectronics devices.

中文翻译：

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具有表面功能化的二维原子厚 (100) 金刚石纳米膜的调制带结构

摘要 利用第一性原理密度泛函理论计算，我们研究了与氢和氟的表面功能化相关的层数 (n) 相关二维 (2D) 原子厚度 (100) 金刚石纳米膜的结构和电子特性。声子色散曲线和从头算分子动力学模拟证明了具有功能化表面的纳米膜具有动态和热稳定性。半功能化纳米膜的带隙在 2.41-2.65 eV 的范围内，与 n 或表面功能化相关，由于未功能化侧的电子特征，其带隙几乎没有变化。对于纳米膜两侧全功能化的情况，带隙大于半功能化二维纳米膜的带隙。这些带隙按照 n 的非线性逆定律减小，这归因于量子限制效应。氟官能化的纳米膜在氢官能化的情况下呈现出更大的带隙。此外，这些二维纳米膜的吸收光谱显示，半功能化纳米膜的吸收边在 2.8 eV 左右，全功能化纳米膜的吸收边在 4.8 eV 左右。基于理论结果，所提出的纳米薄膜可以激发更多的实际应用和制造低维金刚石基光电子器件的努力。半功能化纳米膜为 8 eV，全功能化纳米膜为 4.8 eV。基于理论结果，所提出的纳米薄膜可以激发更多的实际应用和制造低维金刚石基光电子器件的努力。半功能化纳米膜为 8 eV，全功能化纳米膜为 4.8 eV。基于理论结果，所提出的纳米薄膜可以激发更多的实际应用和制造低维金刚石基光电子器件的努力。