Investigation on the conductivity-dependent performance in low voltage cathodoluminescence
With the increase of applied current density in low voltage cathodoluminescence, the exciting power tends to saturate, causing the saturation of electron–hole generation rate in the phosphor layer. Moreover, ground-state depletion could emerge for the activators owing to the increased exciting power and decreased average penetration depth of incident electrons in the phosphor layer, causing the decrease of the energy transfer probability of e–h pairs exciting ground-state activators. In addition, the radiative transition probability of excited activators could be decreased due to the increase of temperature. In view of these key factors, the efficiency decrease in cathodoluminescence is the inevitable result. To restrain the efficiency decrease so as to improve the performance in low voltage cathodoluminescence, the conductivity of the phosphor material was improved. By introducing a conductive component, which improves the conductivity of the phosphor material, the performance in low voltage cathodoluminescence was effectively improved.