Diffusion and nucleation in multilayer growth of PTCDI-C8 studied with in situ X-ray growth oscillations and real-time small angle X-ray scattering.
J Chem Phys
; 146(5): 052803, 2017 Feb 07.
Article
en En
| MEDLINE
| ID: mdl-28178832
ABSTRACT
We study nucleation and multilayer growth of the perylene derivative PTCDI-C8 and find a persistent layer-by-layer growth, transformation of island shapes, and an enhancement of molecular diffusivity in upper monolayers (MLs). These findings result from the evaluation of the ML-dependent island densities, obtained by in situ real-time grazing incidence small angle X-ray scattering measurements and simultaneous X-ray growth oscillations. Complementary ex situ atomic force microscopy snapshots of different growth stages agree quantitatively with both X-ray techniques. The rate and temperature-dependent island density is analyzed using different mean-field nucleation models. Both a diffusion limited aggregation and an attachment limited aggregation model yield in the first two MLs the same critical nucleus size i, similar surface diffusion attempt frequencies in the 1019-1020 s-1 range, and a decrease of the diffusion barrier Ed in the 2nd ML by 140 meV.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Chem Phys
Año:
2017
Tipo del documento:
Article
País de afiliación:
Alemania