GaN growth on sapphire

Large misorientation of GaN films grown on r-plane sapphire substrates by metalorganic vapor-phase epitaxy

“…In the earliest work, GaN was grown on r-plane (1 1 0 2) sapphire since it was the most readily available substrate. The surface morphology was usually quite rough and the electrical property was poor [2]. Most of the research groups avoided using r-plane sapphire substrates to grow GaN devices, because the rough surface makes device fabrication more difficult.…”

Anisotropy of a-plane GaN grown on r-plane sapphire by metalorganic chemical vapor deposition

“…A promising means of eliminating these polarization effects is through the growth of nonpolar wurtzite nitrides. Recently, interest in growth of ð1 1 % 2 0Þ a-plane GaN films on ð1 % 1 0 2Þ ð1 % 1 0 2Þ r-plane sapphire substrates has been greatly increased [6][7][8][9].…”

Crystal growth and characterization of thick GaN layers grown by oxide vapor transport technique

“…Due to the absence of free standing GaN substrates, these devices are fabricated on foreign substrates such as SiC, sapphire, LiGaO 2 or LiGaO 3 [4][5][6][7]. Performance of these devices are reduced due to high dislocation densities resulting from lattice mismatch and thermal expansion coefficient mismatch between the GaN and substrate.…”