Off-axis electron holography in a transmission electron microscope was used to study the charges on threading edge dislocations in n-type GaN (00•1). It was shown that the inner potential was reduced within 10nm of the dislocation. This was consistent with the existence of a negatively charged core. The results could be explained in terms of a simple unscreened potential due to a core charge of about 4 x 107 electrons/cm. Application of the method to other types of dislocation was possible.

Electron Holography Studies of the Charge on Dislocations in GaN. D.Cherns, C.G.Jiao: Physical Review Letters, 2001, 87[20], 205504 (4pp)