Electronic spectroscopy (AES, EELS) and cathodoluminescence (CL) for alpha-Al2O3 characterization

Single crystals of alpha-Al2O3 samples have been characterized by Auger electron spectroscopy (AES), energy loss spectroscopy (EELS) and cathodoluminescence (CL). It has been observed that the prolonged primary electron beam on the alumina surface reduces the carbon impurity without charging the materials and damaging it as it has been seen for SiO2 compound. In less than 3 h, the electron primary beam (E(p) = 4 keV, J(p) 10(-)3 A.Cm-2) was sufficient to remove the carbon impurity. The EELS results recorded for various values of E(p) are not influenced by the action of the primary beam, typical spectra of alumina are obtained. Light emission induced under electron beam irradiation is investigated using the CL technique. The emission from defects in the structure associated with the colour centers (F and F+) is examined at different current densities. The variation of the emission spectra is attributed to the convertion of F+ to F centres at low J(p). (C) 1997 Elsevier Science Ltd. All rights reserved.