The surface potential and defects of insulating materials probed by electron and photon emissions

The influence of heat treatments on /spl alpha/-Al/sub 2/O/sub 3/ samples has been investigated using cathodoluminescence, Auger electron spectroscopy and the SEM mirror method. A significant parameter in charging phenomena is the ability of the material to increase the F/sup +/ emission detected from the 330 nm CL band. The sapphire crystal annealed to high temperature (1700/spl deg/C, 24 hours) may be considered as a stabilized system, including some residual dislocations, with most of the point defects removed and electrically compensated. This is not the case for the polished and not annealed sample which is able to change greatly if the opportunity arises.

[1]  C. Gressus.  The needs for standards: technical terms, materials, characterization and test procedures , 1995 .

[2]  Chen Li,et al.  Dielectric surface preflashover processes in vacuum , 1994 .

[3]  R. Latham,et al.  Photon emission from an alumina insulator in vacuum subjected to DC electrical fields , 1994 .

[4]  Wu,et al.  Radiation-induced electrical degradation in crystalline Al2O3. , 1994, Physical review. B, Condensed matter.

[5]  A. Stoneham.  Radiation effects in insulators , 1994 .

[6]  Bruce D. Evans,et al.  Optical properties of lattice defects in α-Al2O3 , 1994 .

[7]  Stashans,et al.  Calculations of the ground and excited states of F-type centers in corundum crystals. , 1994, Physical review. B, Condensed matter.

[8]  T. Sudarshan,et al.  ANALYSIS OF THE SCANNING ELECTRON MICROSCOPE MIRROR IMAGE BASED ON THE DIELECTRIC SURFACE MICROSTRUCTURE , 1994 .

[9]  G. P. Pells.  Radiation Damage Effects in Alumina , 1994 .

[10]  E. Hodgson.  Radiation enhanced electrical breakdown in Al2O3: field effect , 1992 .

[11]  R. G. Bommakanti,et al.  Flashover in wide-band-gap high-purity insulators : methodology and mechanisms , 1991 .

[12]  G. Blaise,et al.  Charging and flashover induced by surface polarization relaxation process , 1991 .

[13]  N. Itoh,et al.  Electronic excitations, luminescence and lattice defect formation in α-al2O3 crystals , 1991 .

[14]  I. Tale,et al.  Impurity-Associated Colour Centres in Mg- and Ca-Doped Al2O3 Single Crystals , 1981 .

[15]  J. H. Crawford,et al.  Electron centers in single-crystal Al 2 O 3 , 1977 .