Threading dislocations in metal-organic chemical-vapour grown GaN films were imaged non-destructively by the electron channelling contrast imaging technique. Comparisons between electron channelling contrast imaging and cross-sectional transmission electron microscopy indicated that pure edge dislocations could be imaged in GaN by electron channelling contrast imaging. Total threading dislocation densities were measured by electron channelling contrast imaging for various GaN films on engineered 4H-SiC surfaces and ranged from 107 to 109/cm2. A comparison between the ultraviolet electroluminescent output measured at 380nm and the total dislocation density as measured by electron channelling contrast imaging revealed an inverse logarithmic dependence.

Nondestructive Analysis of Threading Dislocations in GaN by Electron Channeling Contrast Imaging. Y.N.Picard, J.D.Caldwell, M.E.Twigg, C.R.Eddy, M.A.Mastro, R.L.Henry, R.T.Holm, P.G.Neudeck, A.J.Trunek, J.A.Powell: Applied Physics Letters, 2007, 91[9], 094106