The measurement of charge on dislocations in GaN by electron holography was described. Recent results were presented showing that edge dislocations in n-doped GaN were highly negatively charged, whereas those in p-doped GaN were positively charged. It was shown that the results were consistent with a model which assumes Fermi level pinning at dislocation states about 2.5V below the conduction band edge. The application of electron holography to screw dislocations, and the dependence of the observations upon the dislocation core structure, were also considered.

Electron Holography Studies of the Charge on Dislocations in GaN. D.Cherns, C.G.Jiao, H.Mokhtari, J.Cai, F.A.Ponce: Physica Status Solidi B, 2002, 234[3], 924-30