Sub-Bandgap Photoemission Correlated with Adsorbed Molecules and. Bulk Impurities in Diamond

摘要

We report on photoemission images from NEA diamond using sub-bandgap and ,near-bandgap photon energies. Emission can be stimulated with photon wavelengths as low as 365 nm, but the low-energy emission disappears after heating the diamond to 700°C, while emission stimulated with 254 and 224 nm photons remains. In both cases the emission occurs only where the concentration of bulk point defects is- low. We explain this behavior as the result of photon absorption both in the bulk and at the surface competing with bulk recombination.