Cold emission characterization using secondary electron emission spectroscopy

Secondary electron emission spectroscopy is used to study the electron transport and emission properties of wide bandgap materials e.g., diamond, BeO.. The secondary electron distribution generated in diamond is found to be dominated by a high concentration of very low-energy electrons, and the emission characteristics of these low-energy electrons is used to deduce information about the cold emission properties of the material. In particular, analysis of the extremely high yields measured from diamond samples indicates that the low-energy electrons have long escape depths in the material. Furthermore, electron energy distribution measurements provide insight into the emission process at various surfaces. The electron transport and emission model inferred from the diamond measurements suggests that diamond and other wide bandgap materials may be promising cold emitter materials, in which case secondary electron emission spectroscopy can be a useful characterization tool. q1999 Elsevier Science B.V. All rights reserved.