Popis: |
The cathodoluminescence edge emission of cadmium telluride at 4.2 °K has been observed, (a) before and after displacement of cadmium atoms or displacement of cadmium and tellurium atoms by monoenergetic electrons, (b) firing in vacuum or an over-pressure of the cation. The intensities of emission bands occurring at 1.555 eV, 1.572 eV and 1.588 eV are enhanced by cadmium displacement and the defect centres responsible for these emissions are believed to involve the first charged state of the cadmium vacancy, the neutral cadmium vacancy and an exciton bound to the neutral cadmium vacancy respectively. The intensity of the emission band at 1.553 eV is enhanced by tellurium displacement or by firing the material in a high cadmium overpressure and is believed to be the double acceptor centre already reported and involving a tellurium vacancy-halogen complex. |