Impact of gas adsorption on the stability and electronic properties of negative electron affinity GaAs nanowire photocathodes
| Autor: | Sihao Xia, Yu Diao, Lei Liu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Band gap 020502 materials Analytical chemistry Nanowire 02 engineering and technology 021001 nanoscience & nanotechnology Surfaces Coatings and Films Electronic Optical and Magnetic Materials Biomaterials Dipole Colloid and Surface Chemistry Adsorption 0205 materials engineering Electron affinity Molecule Work function Direct and indirect band gaps 0210 nano-technology |
| Zdroj: | Journal of Colloid and Interface Science. 572:297-305 |
| ISSN: | 0021-9797 |
| Popis: | The influence of CO, CO2, H2O, H2 and CH4 adsorption on the stability and electronic properties of negative electron affinity (NEA) GaAs nanowire surfaces activated by Cs/O and Cs/NF3 are systematically investigated via first-principles. The calculations indicated that GaAs nanowires activated with 3Cs/O are more susceptible to the surface contamination. After residual gas molecule adsorption, 3Cs/O activated surfaces exhibit direct bandgap character, while 3Cs/NF3 activated surfaces are inversely indirect bandgap. In addition, residual gas adsorption results in a notable increase of band gap, work function and electron affinity of GaAs nanowire surfaces. The incoporation of residual gas molecules also induces a new electric dipole [Cs-gas] with a direction from Cs to gas molecule. From the perspective of theoretical calculation, it is predicted that GaAs nanowires activated through Cs/NF3 has a stronger stability compared with Cs/O in the aspect of gas exposure. |
| Databáze: | OpenAIRE |
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