Abstract
Wide bandgap semiconductors have the possibility of exhibiting a negative electron affinity (NEA) meaning that electrons in the conduction band are not bound by the surface. The surface conditions are shown to be of critical importance in obtaining a negative electron affinity. UV-photoelectron spectroscopy can be used to distinguish and explore the effect. Surface terminations of molecular adsorbates and metals are shown to induce an NEA on diamond. Furthermore, a NEA has been established for epitaxial AlN and AlGaN on 6H-SiC. Field emission measurements from flat surfaces of p-type diamond and AlN are similar, but it is shown that the mechanisms may be quite different. The measurements support the recent suggestions that field emission from p-type diamond originates from the valence band while for AlN on SiC, the field emission results indicate emission from the AlN conduction band. We also report PEEM (photo-electron emission microscopy) and FEEM (field electron emission microscopy) images of an array of nitride emitters.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 694-703 |
| Number of pages | 10 |
| Journal | Applied Surface Science |
| Volume | 130-132 |
| DOIs | |
| State | Published - 1998 |
| Externally published | Yes |
| Event | Proceedings of the 1997 4th International Symposium on Atomically Controlled Surfaces and Intefaces, ACSI-4 - Tokyo, Jpn Duration: Oct 27 1997 → Oct 30 1997 |
ASJC Scopus subject areas
- Chemistry(all)
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films