Vacancy driven surface disorder catalyzes anisotropic evaporation of ZnO (0001) polar surface.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36153312.
- Also identified by DOI 10.1038/s41467-022-33353-2 and PMC identifier 9509323.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The evaporation and crystal growth rates of ZnO are highly anisotropic and are fastest on the Zn-terminated ZnO (0001) polar surface. Herein, we study this behavior by direct atomic-scale observations and simulations of the dynamic processes of the ZnO (0001) polar surface during evaporation. The evaporation of the (0001) polar surface is accelerated dramatically at around 300 °C with the spontaneous formation of a few nanometer-thick quasi-liquid layer. This structurally disordered and chemically Zn-deficient quasi-liquid is derived from the formation and inward diffusion of Zn vacancies that stabilize the (0001) polar surface. The quasi-liquid controls the dissociative evaporation of ZnO with establishing steady state reactions with Zn and O2 vapors and the underlying ZnO crystal; while the quasi-liquid catalyzes the disordering of ZnO lattice by injecting Zn vacancies, it facilitates the desorption of O2 molecules. This study reveals that the polarity-driven surface disorder is the key structural feature driving the fast anisotropic evaporation and crystal growth of ZnO nanostructures along the [0001] direction.