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为了使石墨烯光阴极实现光电转化功能,以超晶格形式掺杂六角氮化硼到石墨烯中,形成杂化纳米带。通过基于第一性原理的计算,从能带结构可以看出,这种方法可以在一个很大的范围内(0~2.5 e V)调控带隙大小。结合能带结构和电荷密度分布分析了带隙调控的机理,此外,运用K-P模型理论分析也得到了一致的结果。以这种方式调控石墨烯材料的带隙,锯齿型边缘和扶手椅型边缘的六角氮化硼/石墨烯(h-BN/graphene)超晶格纳米带,其带隙大小均随着其中h-BN所占比例的增加而变大,而且其带隙大小几乎不受纳米带宽度的影响,这样一来材料的尺寸可以做到更加微型化。再者,基于此方法可以制成渐变带隙结构,进而实现同一光阴极对不同范围光谱的响应。
In order to achieve photoelectric conversion function of graphene photocathode, hexagonal boron nitride is doped into graphene in the form of superlattice to form hybrid nanobelts. Based on the first-principles calculation, it can be seen from the energy band structure that this method can adjust the bandgap size within a very large range (0 ~ 2.5 eV). The mechanism of band gap regulation was analyzed based on the band structure and charge density distribution. In addition, the theoretical analysis of K-P model also obtained consistent results. The bandgaps of graphene materials, serrated edges and armchair edge-shaped hexagonal boron nitride / graphene superlattice nanoribbons are tuned in this manner as the bandgap sizes change with h -BN proportion increases and become larger, and the band gap is almost not affected by the width of the nanobelt, so that the size of the material can be more miniaturized. Furthermore, based on this method, a gradual band gap structure can be made, so that the same photocathode responds to different ranges of spectra.