Open AccessMorphology and defect of a-GaN grown by metal orgamic chemical vapor deposition
Author(s) -
Cui Ying-Chao,
Xie Zili,
Hong Zhang,
Mei Qin,
Li Yi,
Bin Liu,
Lihong Song,
Rong Zhang,
Youdou Zheng
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.8506
Subject(s) - materials science , cathodoluminescence , chemical vapor deposition , scanning electron microscope , isotropic etching , substrate (aquarium) , morphology (biology) , metal , hillock , etching (microfabrication) , crystallography , optoelectronics , composite material , layer (electronics) , metallurgy , chemistry , oceanography , luminescence , geology , biology , genetics
On the substrate of r-sapphires a-GaN films grown by metal orgamic chemical vapor deposition was etched in molten KOH-NaOH for 1.0,1.5 and 2.0 min. Scanning electron microscope, atomic force microscope, X-ray diffraction and cathodoluminescence was used to study its morphology and defect. We find that etching for 1.5 min at the temperature of 400 ℃ is appropriate for a-GaN on sapphires substrate. Different from c-GaN which show hexagonal pits, a-GaN shows parallelogram strips. In the direction of c axis it is easier to be etched. That is because the polarity of a-GaN films is anisotropic which leads to different absorption capacities of OH ions in different directions. We also find hexagonal protuberance on the surface which is associated with threading dislocations.