TY - JOUR
T1 - Dual-polarity GaN micropillars grown by metalorganic vapour phase epitaxy
T2 - Cross-correlation between structural and optical properties
AU - Coulon, P. M.
AU - Mexis, M.
AU - Teisseire, M.
AU - Jublot, M.
AU - Vennéguès, P.
AU - Leroux, M.
AU - Zuniga-Perez, J.
PY - 2014/4
Y1 - 2014/4
N2 - Self-assembled catalyst-free GaN micropillars grown on (0001) sapphire substrates by metal organic vapor phase epitaxy are investigated. Transmission electron microscopy, as well as KOH etching, shows the systematic presence of two domains of opposite polarity within each single micropillar. The analysis of the initial growth stages indicates that such double polarity originates at the micropillar/substrate interface, i.e., during the micropillar nucleation, and it propagates along the micropillar. Furthermore, dislocations are also generated at the wire/substrate interface, but bend after several hundreds of nanometers. This leads to micropillars several tens of micrometers in length that are dislocation-free. Spatially resolved cathodoluminescence and microphotoluminescence show large differences in the optical properties of each polarity domain, suggesting unequal impurity/dopant/vacancy incorporation depending on the polarity.
AB - Self-assembled catalyst-free GaN micropillars grown on (0001) sapphire substrates by metal organic vapor phase epitaxy are investigated. Transmission electron microscopy, as well as KOH etching, shows the systematic presence of two domains of opposite polarity within each single micropillar. The analysis of the initial growth stages indicates that such double polarity originates at the micropillar/substrate interface, i.e., during the micropillar nucleation, and it propagates along the micropillar. Furthermore, dislocations are also generated at the wire/substrate interface, but bend after several hundreds of nanometers. This leads to micropillars several tens of micrometers in length that are dislocation-free. Spatially resolved cathodoluminescence and microphotoluminescence show large differences in the optical properties of each polarity domain, suggesting unequal impurity/dopant/vacancy incorporation depending on the polarity.
UR - http://www.scopus.com/inward/record.url?scp=84899840127&partnerID=8YFLogxK
U2 - 10.1063/1.4870950
DO - 10.1063/1.4870950
M3 - Article
AN - SCOPUS:84899840127
VL - 115
SP - 1
EP - 9
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 15
M1 - 153504
ER -