GaN substrate and GaN homo-epitaxy for LEDs: Progress and challenges<xref ref-type="fn" rid="cpb150941fn1">*</xref>

GaN substrate and GaN homo-epitaxy for LEDs: Progress and challenges*

Wu Jie-Jun, Wang Kun, Yu Tong-Jun†, Zhang Guo-Yi

(a) The photo of 300-μm thick GaN without crack grown on sapphire substrate by PFM method and (b) the AFM image of relatively GaN thick layer over 3 μm ×3 μm scanned area, (c) schematic diagram of the growth mechanism for thick GaN layer using PFM method.^{[ 35 ]}