Radiative and non-radiative recombination at individual dislocations was studied via cathodoluminescence performed in a transmission electron microscope. The dislocations were produced by the indentation of dislocation-free single crystals, and had a-type Burgers vectors (b = 1/3<11•0>). They were aligned along <11•0> directions in the basal plane. A direct correlation between structural and optical properties at the microscopic scale yielded 2 main results: firstly, that 60° basal-plane dislocations exhibited radiative recombination at 2.9eV and, secondly, that screw-type basal-plane dislocations acted as non-radiative recombination centers. The non-radiative recombination was explained by splitting this dislocation into 30° partials that had dangling bonds in the core. The dissociation width of these dislocations was less than 2nm.

Carrier Recombination at Single Dislocations in GaN Measured by Cathodoluminescence in a Transmission Electron Microscope. M.Albrecht, H.P.Strunk, J.L.Weyher, I.Grzegory, S.Porowski, T.Wosinski: Journal of Applied Physics, 2002, 92[4], 2000-5