Characteristics of Multilayered Barium Titanate Films and Their Effect on Thin‐Film Electroluminescent Cells

Abstract

In this work, we fabricated thin‐film electroluminescent (TFEL) cells with a new multilayered layer for the low‐voltage‐driven devices. At first, we performed the voltage accelerated breakdown testing of the multilayered having both high dielectric constant and high breakdown strength. The time‐zero‐breakdown distribution is shown to be dependent on surface roughness, while the long‐term failure studied by time‐dependent dielectric breakdown technique at high field is dependent on the bulk characteristics, i.e., transition layer within multilayered (m‐BT) films. Second, the TFEL devices were prepared using the multilayered as dielectric materials. We observed a decrease of turn‐on voltage with increasing thickness and increase of the maximum overvoltage. Third, typical symmetric capacitance‐voltage and internal charge‐phosphor field characteristics were obtained for the device with thin m‐BT layers. With increasing thickness of m‐BT the significant asymmetry with respect to the applied voltage polarity was observed. This is a main difference as compared with the symmetric characteristics of conventional TFEL devices with low dielectric constant insulators. The experimental results indicate that a selection of the thickness of upper m‐BT and their deposition process would strongly affect the interfacial characteristics as well as bulk characteristics of an as‐grown ZnS:Pr,Ce layer. © 2000 The Electrochemical Society. All rights reserved.