Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

Kun-Dar Li,Jin-Ru Miao

doi:10.1063/1.5021721

Abstract

To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, &lt;100&gt; and &lt;111&gt; preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

Highlights

INTRODUCTIONWhich hinge upon surface facets, would determine the photogenerated charge carriers with tunable redox abilities for catalytic reactions.[14]
By virtue of the energy and environmental crisis, the development of sustainable energy has turned into an extremely important subject for both scientists and engineers over the past decades.[1]
Implementing the numerical calculations of PDEs presented in Eq (9), the formation and evolution of characteristic surface morphologies during anisotropic chemical etching could be presented

Summary

INTRODUCTION

Which hinge upon surface facets, would determine the photogenerated charge carriers with tunable redox abilities for catalytic reactions.[14]. Systematic investigations of the dependence of the surface morphologies on the crystalline orientation would provide a more general insight into the morphological features with the processing parameters.[33] the comprehensive understanding of the etch mechanism may help in improving the practicalities of anisotropic chemical etching techniques in the crystal facet engineering or functional materials fabrication. We expect that this theoretical work might further advance facet-controlled methodologies to explore the peculiarities of these facet-dependent properties for numerous applications

THEORETICAL MODEL

RESULTS AND DISCUSSION

CONCLUSION