Zn doping in the In0.53Ga0.47As(100)beta(2)(2 x 4) surface for negative electron affinity photocathode: A first-principles research
Zn doping in the In0.53Ga0.47As(100)beta(2)(2 x 4) surface for negative electron affinity photocathode: A first-principles research
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用于负电子亲和势光电阴极的 In0.53Ga0.47As(100)β2(2 × 4) 表面中的 Zn 掺杂：第一性原理研究
DOI：
10.1016/j.ijleo.2017.12.127
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发表时间：
2018
期刊：
影响因子：
3.1
通讯作者：
Zhou Lei
中科院分区：
文献类型：
--
作者：
Guo Jing;Long Li;Yang Mingzhu;Zhao Jing;Zhou Lei
InGaAs是一种重要的三元III-V半导体材料，在1-3 μm的近红外区具有良好的光谱响应，负电子亲和势是由In0.53Ga0.47As(100)β2(2 × 4)表面适当敏化产生的。掺杂和敏化是InGaAs光电阴极制备过程中不可缺少的环节。然而，InGaAs的表面掺杂机制尚不清楚。研究了替位锌原子在In0.53Ga0.47As(100)β2(2 × 4)表面敏化的合适掺杂位置。考虑到对称性，得到了8个掺杂位，并建立了8个掺杂面模型。讨论了这些模型的表面原子结构和表面形成能。形成能越低，表面越稳定。从形成能分析可知，较稳定的掺杂模型为Zn4和Zn5。在此基础上，进一步讨论了这两种掺杂模型的能带结构、表面电荷分布、功函数和光学性质。锌掺杂表面比锌掺杂表面具有更低的功函数和反射率，在1-3 μm范围内具有更好的吸收。综上所述，掺锌的InGaAs表面更有利于光电子的输运和光电子发射。因此，Zn4是InGaAs光阴极最有利的掺杂位置。
InGaAs is an important ternary III-V semiconductor material with good spectral response in the near infrared region of 1–3 μm. The negative electron affinity is generated from the proper sensitization of In0.53Ga0.47As(100)β2(2 × 4) surface. Doping and sensitization are indispensable in the preparation of InGaAs photocathode. However, the surface doping mechanism of InGaAs is not clear. This article focuses on the suitable doping sites of substitutional Zn atoms for sensitization on In0.53Ga0.47As(100)β2(2 × 4) surface. Considering the symmetry, there are eight doping sites and the eight doping surface models are formed. The surface atomic structures and surface formation energies of these models are discussed. The lower the formation energy is, the more stable the surface is. Zn4 and Zn5 are the more stable doping models based on the analysis of formation energy. Therefore the band structure, surface charge distribution, work function and optical properties are further discussed for these two doping models. The Zn4 doping surface has a lower work function and reflectivity and better absorption in the range of 1–3 μm than Zn5. In a word, the InGaAs surface with Zn4 doped is more conducive to the photoelectrons transport and photoemission. Then Zn4 is the most favorable doping site for the InGaAs photocathode.