The density and types of threading dislocations in InN thin films grown on (00▪1) sapphire with a GaN buffer layer were characterized by using transmission electron microscopy. Perfect edge threading dislocations with 1/3<11▪0> Burgers vectors were the predominant defects which penetrated the GaN and InN layers. Pure screw and mixed threading dislocations were also observed. Overall, the threading dislocation density decreased during film growth; due to annihilation and fusion. The threading dislocation density in GaN was as high as about 1.5 x 1011/cm2, and fell rapidly to about 2.2 x 1010/cm2 in InN films. Most half-loops in GaN were connected with misfit dislocation segments at the InN/GaN interface, and formed loops, while some threading dislocations segments threaded the interface. Half-loops were also generated during the initial stages of InN growth.

Threading Dislocations in Epitaxial InN Thin Films Grown on (0001) Sapphire with a GaN Buffer Layer. C.J.Lu, L.A.Bendersky, H.Lu, W.J.Schaff: Applied Physics Letters, 2003, 83[14], 2817-9