QUALITY ASSESSMENT OF MGO SUBSTRATE MATERIALS FOR HIGH T-C SUPERCONDUCTOR THIN-FILMS USING CATHODOLUMINESCENCE MICROSCOPY

Cathodoluminescence (CL) microscopy has been used to investigate the l uminescence response of MgO single crystal substrates intended for hig h T-c superconductor applications. Wavelength resolved CL spectra have been collected from both the surface and the bulk of the MgO single c rystals, under different preparatory treatments. It was found that ann ealing the MgO resulted in the reduction of luminescent surface defect states present in the as-received and ion milled samples and at sites of surface damage. The surface treatment given to MgO single crystals can significantly affect the electrical properties of high T-c superc onducting thin films deposited on them.