Strong mesoscopic transverse growth suppression in high-speed unidirectional growth of KDP single crystals

TL;DR

This study reveals a unique mesoscopic transverse growth arrest in high-speed unidirectional KDP crystal growth, explained by a new molecular-orientation-selective self-shielding mechanism, aligning well with experimental observations.

Contribution

Introduces a novel set of surface concentration rate equations and a molecular-orientation-selective self-shielding model to explain unique growth morphology in KDP crystals.

Findings

Strong transverse growth arrest observed in high-speed KDP growth

Molecular-orientation-selective self-shielding explains growth suppression

Model aligns with experimental growth data

Abstract

We show a strong mesoscopic transverse growth arrest that co-exists with a high-speed longitudinal growth in single-crystalline KDP crystals with large aspect ratios. To explain this unique growth morphology, which cannot be explained by any current theories, we introduce a new set of surface concentration rate equations and demonstrate a molecular-orientation-selective surface self-shielding and channeling mechanism. We introduce a local supersaturation and calculate crystal growth driving force and growth rate, demonstrating quick arrest of both quantities as results of molecule-orientation selectivity based self-shielding and channeling effects. The growth dynamics thus derived can satisfactorily explain all experimental observations in single-crystalline KDP crystal growth reported here.