A detailed study was made of the luminescence at 3.42eV which was usually

observed in a-plane epitaxial lateral overgrowth GaN; grown by hydride vapour

phase epitaxy onto r-plane sapphire. This band was related to the radiative

recombination of excitons in a commonly encountered extended defect of a-plane

GaN: the I1 basal stacking fault. Cathodoluminescence measurements showed that

these stacking faults were essentially located in the windows and the N-face wings

of the epitaxial lateral overgrowth GaN and that they could appear isolated, as well

as organized into bundles. Time-integrated and time-resolved photoluminescence,

supported by a qualitative model, revealed not only efficient trapping of free

excitons by basal-plane stacking faults but also some localization within I1 stacking

faults themselves. Measurements made at room temperature showed that free

excitons recombined efficiently with rather long luminescence decay times

(360ps); comparable to those encountered in high-quality GaN epilayers. The

possible role of I1 stacking faults in the overall recombination mechanism of

excitons was considered.

Exciton Localization on Basal Stacking Faults in a-Plane Epitaxial Lateral

Overgrown GaN Grown by Hydride Vapour Phase Epitaxy. P.Corfdir, P.Lefebvre,

J.Levrat, A.Dussaigne, J.D.Ganière, D.Martin, J.Ristić, T.Zhu, N.Grandjean,

B.Deveaud-Plédran: Journal of Applied Physics, 2009, 105[4], 043102