稀土掺杂黑磷的第一性原理计算

发布时间：2018-06-16 20:33

本文选题：第一性原理 + 黑磷　；参考：《伊犁师范学院》2017年硕士论文

【摘要】：本文采用第一性原理计算方法,主要计算了纯黑磷、N单掺杂黑磷、稀土元素(Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb)单掺杂黑磷以及分别与N共掺杂黑磷的能带结构、态密度和光学性质,计算分析的结果如下:首先计算分析了纯黑磷的能带结构、态密度和光学性质,计算得到纯黑磷的禁带宽度为0.967e V,且导带主要由P的3p态贡献,而价带主要由P的3p态和3s态贡献。光学性质方面,纯黑磷的介电实部ε2,静介电常数值为6.55;介电虚部ε2主要有两个明显的峰,分别出现在3.45e V和5.69eV;吸收峰在能量为6.55eV处达到最大峰级2.44×105 cm-1;反射谱的主峰在7.4e V处,能量损失峰在12.9eV附近。然后计算分析了N单掺杂黑磷的能带结构、态密度和光学性质,掺杂后的禁带宽度要略小于纯黑磷的禁带宽度。N单掺杂黑磷后,N与周围的P相互作用,导带和价带的能级数目也明显增多。光学性质方面,N单掺杂黑磷的静介电常数要小于纯黑磷的静介电常数,导电性增强;比较N单掺杂黑磷和纯黑磷的介电虚部峰、吸收谱主峰、反射谱主峰和折射谱主峰的位置变化,发现主峰位置都向低能方向移动,发生了红移现象。最后计算分析了稀土元素单掺杂以及分别与N共掺杂黑磷的能带结构、态密度和光学性质,从能带结构可以看出,掺杂后的禁带宽度要小于纯黑磷的禁带宽度,除Ce与N共掺杂和Yb单掺杂,Ce与N共掺杂黑磷的导带和价带重合呈现出了金属性,而Yb单掺杂黑磷的禁带宽度要稍微大于纯黑磷的禁带宽度。导带和价带的能级数目也明显增多,这是稀土元素单掺杂和与N共掺杂黑磷后,稀土元素与周围的P相互作用。从态密度图可以发现,从Ce往后的元素掺杂,则是由4f态贡献较多,而Sc、Y、La单掺杂和共掺杂的态密度峰主要由3d、4d、5d态贡献,这是由于从Ce元素开始的元素拥有4f态电子。从光学性质图看出,纯黑磷、稀土元素单掺杂黑磷和稀土元素与N共掺杂黑磷的介电虚部图、吸收谱图、反射谱图和能量损耗图,发现在低能部分差别较大,当能量大于12.5eV后,变化趋势趋于一致;比较介电虚部峰、吸收谱主峰、反射谱主峰和折射谱主峰的位置变化,发现主峰位置都向低能方向移动,因此可以判断单掺杂和共掺杂后发生了红移现象。
[Abstract]:In this paper, the energy band structure, density of states and optical properties of pure black phosphorus and its monodoped black phosphorus, the rare earth element scabs, the rare earth element, the rare earth, the rare earth The results of calculation and analysis are as follows: firstly, the band structure, density of states and optical properties of pure black phosphorus are calculated and analyzed. The band gap of pure black phosphorus is 0.967e V, and the conduction band is mainly contributed by the 3p state of P. The valence band is mainly contributed by the 3p and 3s states of P. In terms of optical properties, the dielectric constant value of pure black phosphorus is 6.55, the dielectric imaginary 蔚 _ 2 has two main peaks, which are 3.45e V and 5.69 EV, the absorption peak reaches the maximum peak level of 2.44 脳 10 ~ 5 cm ~ (-1) at 6.55 EV, and the main peak of reflection spectrum is at 7.4e V. The energy loss peak is about 12.9 EV. Then, the energy band structure, density of states and optical properties of N-doped black phosphorus are calculated and analyzed. The bandgap after doping is slightly smaller than that of pure black phosphorus. The number of energy levels of conduction band and valence band also increased obviously. In terms of optical properties, the static dielectric constant of N-doped black phosphorus is smaller than that of pure black phosphorus, and its conductivity is enhanced. It is found that the position of the main peak of the reflection spectrum and the main peak of the refraction spectrum are all moving towards the direction of low energy, and the phenomenon of red shift occurs. Finally, the band structure, density of states and optical properties of rare earth elements doped and co-doped with N respectively are calculated and analyzed. From the band structure, it can be seen that the bandgap of doped black phosphorus is smaller than that of pure black phosphorus. Except ce and N co-doping and Yb mono-doped ce and N co-doped black phosphorus, the conduction band and valence band coincidence showed gold properties, while the band gap of Yb monodoped black phosphorus was slightly larger than that of pure black phosphorus. The energy levels of conduction band and valence band also increased obviously. This is the interaction of rare earth element with the surrounding P after single doping of rare earth element and co-doping of black phosphorus with N. From the density diagram of states, it can be found that the doping from ce is mainly due to the contribution of 4f state, while the peak of state density of single doping and co-doping of ScPY La is mainly contributed by the 5d state of 3dU 4dn, which is due to the fact that the element starting from ce has 4f state electrons. It can be seen from the optical properties diagram that pure black phosphorus, rare earth element monodoped black phosphorus and rare earth element co-doped black phosphorus with N are the dielectric imaginary part, absorption spectrum, reflection spectrum and energy loss diagram. It is found that there is a great difference in the low energy part, when the energy is more than 12.5 EV, the optical properties of pure black phosphorus, rare earth element doped black phosphorus and rare earth element co-doped black phosphorus with N are more than 12.5eV. The change trend tends to be the same, and comparing the position of the main peak of dielectric imaginary peak, absorption spectrum, reflection spectrum and refraction spectrum, it is found that the position of the main peak moves to the direction of low energy, so it can be judged that the red shift occurs after single doping and co-doping.
【学位授予单位】：伊犁师范学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O469

【参考文献】