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Comparative study of Cs,O coadsorption on Ga0.75Al0.25N (0001) and (001) surfaces

  • Mingzhu YangEmail author
  • Jing Guo
  • Zhanhui Liu
  • Xiaoqian Fu
Article
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Abstract

Based on first principle calculations, we carried out comparative research of Cs,O coadsorption on Ga0.75Al0.25N (0001) surface and Ga0.75Al0.25N (001) (2 × 2) reconstruction surface. On the (0001) surface, the average coordinate difference between Cs and O atoms along [0001] direction is obviously smaller than that along [001] direction on (001) (2 × 2) reconstruction surface. This is due to the existence of dimers and trenches on the (001) (2 × 2) reconstruction surface. Cs atoms are favored to locate on the dimers while O atoms are favored to locate in the trenches. As a result, Cs–O dipoles on (001) (2 × 2) reconstruction surface make an important contribution on lowering work function. For both (0001) and (001) (2 × 2) reconstruction surface, work function values fluctuate up and down at the stage of Cs,O alternative adsorption, and the valley values are smaller and smaller. The site of Mg dopant has an influence on work function of the surfaces, which results in the “fish scale field” effect.

Keywords

Ga0.75Al0.25N (0001) surface Ga0.75Al0.25N (001) (2 × 2) reconstruction surface Work function Cs–O dipole “Fish scale field” effect 

Notes

Acknowledgements

This study was funded by Natural Science Foundation of Jiangsu Province (Grant No. BK20170959), National Natural Science Foundation of China (Grant Nos. 61705108, 61704075 and 61601198), and the startup foundation for introducing talent of NUIST (Grant No. 2016r039). The authors acknowledge National Supercomputing Center in Shenzhen for providing the computational resources.

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Authors and Affiliations

  1. 1.School of Physics and Optoelectronic EngineeringNanjing University of Information Science and TechnologyNanjingChina
  2. 2.School of AutomationNanjing Institute of TechnologyNanjingChina
  3. 3.School of Information Science and EngineeringUniversity of JinanJinanChina

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