Morphologies and plane indices of pyramid patterns on wet-etched patterned sapphire substrate

Abstract

A wet etching process was employed to investigate the evolution of pyramids on the patterned sapphire substrate (PSS). It has been found that the PSS comprised a hexagonal pyramid covered with six facets {3 (4) over bar 1 7} when disk-shaped SiO2 mask still remained. Three facets {1 (1) over bar 0 5} were exposed when mask was etched away. In this study, a continuous etching process was performed. It was found that another six facets {4 (5) over bar 1 30} and another three facets {1 (1) over bar 0 10} appeared on the bottom and the top of pyramid. Finally, when the etching time reached around 5 min, most of pyramids on the PSS disappeared. (C) 2013 Elsevier B.V. All rights reserved.