Abstract
The excitation spectra for two intrinsic luminescence bands at 3.76 eV (UV) and 2.62 eV (BG) in PbCl2 have been measured using synchrotron radiation in the energy range up to 25 eV at 10 K. Since the UV and BG bands are connected to excitonic luminescence and electron–hole (e–h) recombination luminescence, respectively, an analysis of the difference in their excitation spectra allows us to separate excitonic and e–h mechanisms in the multiplication of electronic excitations. It is found that the intensity of the UV emission is sharply increased at 9.8 eV, which is higher than twice the band gap energy. Secondary excitons are formed by inelastic scattering of hot photoelectrons in the region above 9.8 eV. On the other hand, the BG emission is gradually enhanced in the range of 9–12.5 eV, and the intensity doubles at around 12.5 eV. This result indicates that the creation of two e–h pairs per photon predominantly causes in the region above 12.5 eV. The e–h multiplication originates not only in inelastic scattering of hot photoelectrons in the 12.5–25 eV range but also in interband Auger recombination of holes in the Cl− core levels with valence electrons in the 18–25 eV range.
