Exploring optoelectronic properties of C-doped GaAs for photocathode application from first-principles calculation

In the preparation process of negative electron affinity GaAs photocathodes, the p-type doped property is beneficial to photoemission, and the doping element is usually Be or Zn. In fact, C-doped GaAs material has been widely used due to its high activation rate, extremely low diffusion coefficient,...

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Bibliographic Details
Published in:AIP advances 2022-01, Vol.12 (1), p.015106-015106-7
Main Authors: Guo, Xin, Shi, Feng, Zhang, Yijun, Zhang, Ruoyu, Qiu, Hongjin
Format: Article
Language:English
Subjects:
Absorptivity
Angular distribution
Density functional theory
Diffusion coefficient
Diffusion rate
Directivity
Dopants
Electron affinity
Electron mass
Energy gap
First principles
Forbidden bands
Gallium arsenide
Mathematical analysis
Negative electron affinity
Optical properties
Optoelectronics
Photocathodes
Photoelectric emission
Photoelectrons
Thermal stability
Valleys
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Summary:In the preparation process of negative electron affinity GaAs photocathodes, the p-type doped property is beneficial to photoemission, and the doping element is usually Be or Zn. In fact, C-doped GaAs material has been widely used due to its high activation rate, extremely low diffusion coefficient, and good thermal stability, whereas the influence mechanism of the C dopant on the performance of the GaAs photocathode is still unclear. In order to investigate the substitutional effect on C-doped GaAs, electronic structures and optical properties along with angular distribution of emitted photoelectrons are obtained by utilizing first-principles calculation based on density functional theory. The results show that C-doped GaAs is more likely to form a p-type doped feature in which the C dopant forms new levels in the forbidden band and reduces the energy gap as well as increasing the absorption coefficient and decreasing the reflectivity in the visible light band. In addition, the electrons emitted from the Γ-valley for C-doped GaAs have better directivity than those for pure GaAs, which is mainly ascribed to the smaller effective electron mass in the Γ-valley.
ISSN:2158-3226
2158-3226
DOI:10.1063/5.0073844