OPTICAL CHARACTERISATION OF ZnO

摘要

The green (2.19 eV) and yellow (1.99 eV) luminescence bands in ZnO polycrystalline samples were studied by photoluminescence, excitation luminescence, time resolved spectroscopy and lifetime measurements. A thermal population of the optical centers have been found for temperatures above 35K accompanied with a high energy shift of the band maximum indicating that at least two excited states 150 meV apart are involved in the recombination processes.