ELECTRONIC SPECTROSCOPY (AES, EELS) AND CATHODOLUMINESCENCE (CL) FOR ALPHA-AL2O3 CHARACTERIZATION

Single crystals of alpha-Al2O3 samples have been characterized by Auge r electron spectroscopy (AES), energy loss spectroscopy (EELS) and cat hodoluminescence (CL). It has been observed that the prolonged primary electron beam on the alumina surface reduces the carbon impurity with out charging the materials and damaging it as it has been seen for SiO 2 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 b y the action of the primary beam, typical spectra of alumina are obtai ned. Light emission induced under electron beam irradiation is investi gated using the CL technique. The emission from defects in the structu re associated with the colour centers (F and F+) is examined at differ ent current densities. The variation of the emission spectra is attrib uted to the convertion of F+ to F centres at low J(p). (C) 1997 Elsevi er Science Ltd. All rights reserved.