Abstract
By using density functional theory, we have investigated the Cs adsorption mechanism of Mg-doped GaN nanowire photocathode. The results show that in the GaN nanowire, Mg atoms tend to replace the Ga atoms in the central position, because the position has the lowest formation energy, and the carrier concentration is highest, which shows better conductivity. Besides, Mg doping leads to the Fermi level close to the valence band, exhibiting p-type conductivity. After Cs activation, the most stable adsorption site of Mg-doped nanowires is B N site. After Cs adsorption, the conduction band minimum and the valence band maximum both move to the lower energy, which is favorable for forming the n-type surface state and improving the photoelectron escape probability. This study can be used to guide the Cs adsorption process of Mg-doped GaN nanowires, which is helpful to improve the performance of GaN nanowire-based optoelectronic devices.
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Acknowledgements
The authors would like to thank Meishan Wang of School of Information and Electrical Engineering, Ludong University during the DFT calculations. This work is sponsored by Qing Lan Project of Jiangsu Province-China, the Fundamental Research Funds for the Central Universities-China (Grant No. 30916011206) and the Six Talent Peaks Project in Jiangsu Province-China (Grant No. 2015-XCL-008).
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Xiao, P., Liu, L., Gao, P. et al. Theoretical study on electronic properties of p-type GaN nanowire surface covered with Cs. Opt Quant Electron 50, 86 (2018). https://doi.org/10.1007/s11082-018-1360-0
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DOI: https://doi.org/10.1007/s11082-018-1360-0