Correlation between Light Microscopical and Electron Microscopical Images of Crystal Defects in GaP

Ultramicroscopy and dark-field-illumination basing on the scattering of photons are easily available, they are nondestructive light microscopical methods for real structure investigations of semiconducting materials. The observation of dislocations is possible because of photon scattering at precipitations adherent to the dislocation line. This work gives a direct correlation between light microscopical and electron microscopical images of dislocations and in this way some hints on the nature of scattering centres. The light scattering takes place at precipitations caused due to gettering of impurity atoms by the dislocation line. Besides elongated dislocations prismatic loops were observed. The loop density was found to be in the order of magnitude of about 10¹² cm⁻³ which corresponds to a concentration of about 10¹⁷ atoms contained in the loops in good agreement with the concentration of impurities in the crystals.