Exploration on structural stability, electronic and optical properties of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin film and nanowire photocathode surface.
J Phys Condens Matter
; 35(47)2023 Aug 30.
Article
en En
| MEDLINE
| ID: mdl-37579759
ABSTRACT
To explore effects of surface activation on AlGaN-based photocathode, this paper analyzes in detail the structural stability, charge transfer, band structure, density of states, absorption coefficient and reflectivity of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin films and nanowires by using first-principles. Our results reveal that adsorption energy of Al0.5Ga0.5N thin films and nanowires adsorbed by Cs will gradually increase as Cs coverage increases, and structural stability will be weakened. Cs-adsorbed thin film surfaces are more stable than nanowire when Cs coverage is same. Cs/O co-adsorbed Al0.5Ga0.5N systems are more stable under high Cs coverage. And Cs/O co-adsorbed Al0.5Ga0.5N possess the most stable structure when the ratio of Cs to O is 21. Band structure and density of states imply that Cs and O adsorption introduce new energy levels, which are derived from s, p orbitals of Cs and s orbitals of O, respectively. Furthermore, only when the Cs/O ratio is 21, the work function of Al0.5Ga0.5N thin film is lower than that of Cs-only adsorption, which is conducive to electron escape and improving quantum efficiency. Results of optical properties show that Cs activation and Cs/O activation can greatly improve the optical performance of Al0.5Ga0.5N.
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01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Condens Matter
Asunto de la revista:
BIOFISICA
Año:
2023
Tipo del documento:
Article