Improved luminance and efficiency of ZnS:Mn and GaN:Eu TDEL devices using PZT thick dielectric films

In this paper, we report on the optimization of TDEL devices in both the phosphor material and the device structure. The TDEL device consists of a metal-insulator-semiconductor-insulator-metal (MISIM) stacked film structure built upon a transparent glass substrate. The high dielectric constant and break down field of PZT thick dielectric film along with the other thin film stacks has enabled a significantly higher charge (>3 μC/cm²) transport across the phosphor layer. Furthermore, the nano-porous PZT film has reduced the intensity of high field points in the device, resulting in a steeper luminance-voltage slope after device turn-on. We have also found that the phosphor electric field of the TDEL surpasses that of a thin film electroluminescent (TFEL) device, resulting in higher efficiencies under same biasing conditions.