An Experimental Proof of Radiative Recombination Mechanisms of Electron‐Hole Pairs at Activator Ions

Abstract

It has been shown that the concentration dependence curve of activator luminescence provides us with a powerful tool in studying cathodoluminescence. The experimental results reveal the excitation mechanisms of activator ions by irradiation of electron beam on phosphor crystals; two excitation mechanisms should be considered: (i) direct excitation by incident electrons, including internally generated secondary electrons; and (ii) indirect excitation through the mobile electron and holes generated by incident electrons. The experimental results also suggest a possible model that (iii) radiative recombination of electron‐hole pairs only occurs at the activator ions showing two valences at the ordinary conditions, and (iv) the type of radiative recombination process at the activator ions is determined by the type of carrier which is first trapped.