The two-dimensional (2D) C₃N has emerged as a material with promising applications in high performance device owing to its intrinsic bandgap and tunable electronic properties. Although there are several reports about the bandgap tuning of C₃N via stacking or forming nanoribbon, bandgap modulation of bilayer C₃N nanoribbons (C₃NNRs) with various edge structures is still far from well understood. Here, based on extensive first-principles calculations, we demonstrated the effective bandgap engineering of C₃N by cutting it into hydrogen passivated C₃NNRs and stacking them into bilayer het-erostructures. It was found that armchair (AC) C₃NNRs with three types of edge structures are all semiconductors, while only zigzag (ZZ) C₃NNRs with edges composed of both C and N atoms (ZZ-CN/CN) are semiconductors. The bandgaps of all semiconducting C₃NNRs are larger than that of C₃N nanosheet. More interestingly, AC-C₃NNRs with CN/CN edges (AC-CN/CN) possess direct bandgap while ZZ-CN/CN have indirect bandgap. Compared with the monolayer C₃NNR, the bandgaps of bilayer C₃NNRs can be greatly modulated via different stacking orders and edge structures, varying from 0.43 eV for ZZ-CN/CN with AB’-stacking to 0.04 eV for AC-CN/CN with AA-stacking. Particularly, transition from direct to indirect bandgap was observed in the bilayer AC-CN/CN heterostructure with AA’-stacking, and the indirect-to-direct transition was found in the bilayer ZZ-CN/CN with AB-stacking. This work provides insights into the effective bandgap engineering of C₃N and offers a new opportunity for its applications in nano-electronics and optoelectronic devices.

中文翻译：

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通过范德华堆叠调整氢钝化的C 3 N纳米带的电子性质

二维（2D）C ₃ N由于其固有的带隙和可调节的电子特性，已成为在高性能器件中具有广阔应用前景的材料。尽管有几篇有关通过堆叠或形成纳米带对C ₃ N进行带隙调节的报道，但对具有各种边缘结构的双层C ₃ N纳米带（C ₃ NNR）的带隙调制的了解仍很远。在这里，基于大量的第一性原理计算，我们通过将C ₃ N切成氢钝化的C ₃ NNRs并将其堆叠成双层异质结构，证明了其有效的带隙工程。发现扶手椅（AC）C ₃具有三种边缘结构的NNR都是半导体，而只有具有由C和N原子组成的边缘的Z字形（ZZ）C ₃ NNR（ZZ-CN / CN）是半导体。所有半导体C ₃ NNR的带隙均大于C ₃ N纳米片的带隙。更有趣的是，具有CN / CN边缘（AC-CN / CN）的AC-C ₃ NNR具有直接带隙，而ZZ-CN / CN具有间接带隙。与单层C ₃ NNR相比，双层C ₃的带隙NNR可以通过不同的堆叠顺序和边缘结构进行很大的调制，范围从具有AB'堆叠的ZZ-CN / CN的0.43 eV到具有AA堆叠的AC-CN / CN的0.04 eV不等。特别地，在具有AA'堆叠的双层AC-CN / CN异质结构中观察到从直接带隙到间接带隙的转变，并且在具有AB堆叠的双层ZZ-CN / CN中发现了间接至直接的转变。这项工作为C ₃ N的有效带隙工程研究提供了见识，并为其在纳米电子和光电子器件中的应用提供了新的机会。