Characteristics of multilayered barium titanate films and their effect on thin-film electroluminescent cells

• Published in: Journal of the Electrochemical Society 2000-11, Vol.147 (11), p.4374-4378
• Main Authors: LEE, Yun-Hi, OH, Jung-Hoon, JU, Byeong-Kwon, OH, Myung-Hwan
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Optoelectronic devices; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.1394072

Thin film electroluminescent (TFEL) cells were fabricated with a multilayered BaTiO3 layer for application as low-voltage-driven devices. Voltage accelerated breakdown testing was first performed on the multilayered BaTiO3 which had 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 the time-dependent dielectric breakdown technique is dependent on the bulk characteristics, i.e., the transition layer within the multilayered BaTiO3 (m-BT) films. Secondly, the TFEL devices were prepared using the multilayered BaTiO3 as the dielectric material. A decrease of turn-on voltage with increasing thickness and increase of the maximum overvoltage was observed. Thirdly, 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, 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 the deposition process would strongly affect the interfacial characteristics as well as bulk characteristics of an as-grown ZnS:Pr,Ce layer. 10 refs.