Cathodoluminescence imaging was used to study the onset of plastic relaxation and critical thickness for misfit dislocation formation by basal plane or non-basal plane slip in In0.09Ga0.91N/GaN heterostructures grown on non-polar (10•0) and semi-polar (30•¯1) substrates. Layers grown on both orientations were shown to stress relax initially via generation of non-basal plane misfit dislocations as a result of prismatic slip on inclined m-planes. Analysis of the resolved shear stress on the two slip planes (i.e., basal and an inclined m-plane) revealed a crossover at which the resolved shear stress on the m-planes became larger than that on the basal plane.

Stress Relaxation and Critical Thickness for Misfit Dislocation Formation in (10¯10) and (30¯3¯1) InGaN/GaN Heteroepitaxy. P.S.Hsu, M.T.Hardy, E.C.Young, A.E.Romanov, S.P.DenBaars, S.Nakamura, J.S.Speck: Applied Physics Letters, 2012, 100[17], 171917