Design of patterned sapphire substrates for GaN-based light-emitting diodes<xref ref-type="fn" rid="cpb150397fn1">*</xref>

Design of patterned sapphire substrates for GaN-based light-emitting diodes*

Wang Hai-Yan^a), Lin Zhi-Ting^a), Han Jing-Lei^a), Zhong Li-Yi^a), Li Guo-Qiang^a),^b)

SEM images of hexagonal frustums:^{[ 28 ]} (a) top view; (b) cross section view.