Electronic and optical properties of Zn-doped InGaAs emission layer with vacancy defects: A DFT study
Electronic and optical properties of Zn-doped InGaAs emission layer with vacancy defects: A DFT study
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DOI：
10.1016/j.ijleo.2017.06.056
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发表时间：
2017-08
期刊：
影响因子：
3.1
通讯作者：
Jing Guo;Minhua Zhou;J. Zhao;Lei Zhou;Liansong Xiong
中科院分区：
文献类型：
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作者：
Jing Guo;Minhua Zhou;J. Zhao;Lei Zhou;Liansong Xiong
In_（0.53）Ga_（0.47）As是短波近红外负电子亲和势光电阴极的重要材料。Zn原子被掺杂在本征InGaAs中以形成p型In 0.53Ga 0.44Zn 0.03As发射层。本文建立了Zn掺杂In_（0.53）Ga_（0.44）Zn_（0.03）As体材料的In、Ga、As空位缺陷模型。重点研究了缺陷对掺锌InGaAs发光层的微结构和光学性能的影响。进一步研究了空位缺陷和掺杂Zn原子对光电子发射性能的综合影响。从形成能的分析表明In或Ga空位缺陷比As更容易产生。考虑到材料的极性，As空位缺陷更有利于光电子的发射，因为As空位缺陷是一个正中心，与掺杂Zn原子相互作用产生受主能级，使能隙变窄。同时，当As空位缺陷出现时，Zn离子更容易接受电子。具有As空位缺陷的InGaAs发光层的吸收系数也大于具有In或Ga缺陷的InGaAs发光层。因此，As空位缺陷有利于提高InGaAs光电阴极的光电发射性能，而In或Ga空位缺陷则应避免。
In0.53Ga0.47As is an important material for the shortwave near-infrared negative electron affinity photocathodes. Zn atoms were doped in the intrinsic InGaAs to form p-type In0.53Ga0.44Zn0.03As emission layer. Models of Zn-doped In0.53Ga0.44Zn0.03As bulk with In, Ga or As vacancy defect were built in the article. Emphasis was put on how the defects influence the microstructure and the optical properties of the Zn-doped InGaAs emission layer. Combined effect of both vacancy defects and doped Zn atoms for the photoelectron emission performance was further studied. It is indicated that the In or Ga vacancy defect is easier to be generated than the As from the analysis of formation energy. However, As vacancy defect is more benefit for photoelectrons emission considering the material polarity because As vacancy defect interacting with doped Zn atoms is a positive center and generates acceptor level to narrow the energy gap. At the same time Zn ion will be easier to accept electrons when the As vacancy defect appears. The absorption coefficient of the InGaAs emission layer with As vacancy defect is also bigger than that with In or Ga defect. In conclusion, As vacancy defect is benefit and will promote the photoemission of InGaAs photocathode while the In or Ga vacancy defect should be avoided when the emission layer is grown.