59.4: Novel Device Structure of Field Effect — Ferroelectric Electron Emitter

Sato

Mori

et al. 2009

jjap

A factor causing deterioration of a ferroelectric electron emitter with a unique porous electrode has been investigated. In an electron emitter that deteriorates upon continuous operation, a decrease of the remnant polarization and a discoloration of the ferroelectric layer were observed. Furthermore, the binding energies of the elements comprising the layer were shown to have shifted to a higher energy when the ferroelectric layer was analyzed by X-ray photoelectron spectroscopy (XPS). These results indicate polarization fatigue caused by oxygen vacancies in the ferroelectric layer. Therefore, we considered that the main factor causing deterioration of our electron emitter is polarization fatigue in the ferroelectric layer. On the basis of these investigations, we applied a new ferroelectric material supplemented with 1 wt % MnO 2 to prevent the degradation of the ferroelectric layer, which resulted in the durability of the electron emitter improving significantly.

Section: Introductionmentioning

confidence: 92%

Investigation of Factor Causing Deterioration of Ferroelectric Electron Emitter

Sato

Mori

et al. 2009

jjap

“…On the other hand, we developed an electron emitter in which an upper electrode with numerous micro-holes is arranged so as to not contact the ferroelectric surface, thus forming a vacuum gap. In 2004-2005, we used such an electron emitter to fabricate a prototype field emission display with diagonal size of 4.3 inches, and used it to render 128 gray-scale video [7,8]. However, the role of the vacuum gap in the electron emission mechanism remained unclear.…”

Section: Introductionmentioning

confidence: 99%

A ferroelectric electron emitter having a vacuum gap

Ohwada

Nanataki

2009

Elect Comm in Japan

SUMMARYA novel electron emitter utilizing the characteristics of ferroelectric ceramic materials has been developed. The electron-emitting portion of the electron emitter has a unique micro-structure which has the vacuum gap between an upper electrode and the surface of a ferroelectric layer. We confirmed electron emission by a three-step process which consists of electron charge (the first step), charge retention (the second step), and electron emission (the third step). The ferroelectric hysteresis in the process indicates unique characteristics as follows. At the first step, remnant polarization of the same level as the completely adhered electrode structure is obtained in spite of a vacuum gap because the electron charge develops from the upper electrode to the surface of the ferroelectric layer under the vacuum gap in synchronism with the polarization reversal of the ferroelectric layer. On the other hand, at the third step, the electric field in the vacuum gap advances electron emission while the development of the polarization reversal inhibits the return of the electron charge along the surface of the ferroelectric layer.

“…In 2004 and 2005, we published a novel ferroelectric electron emitter that has a unique microstructure of electron-emitting portions formed between the upper electrode and the surface of the ferroelectric layer. 7,8) By utilizing the ferroelectric emitters as subpixels, we demonstrated a moving colored image using 128 gray scales per color displayed on a 4.3-in. prototype fieldemission display.…”

Section: Introductionmentioning

confidence: 99%

Electrode Structure of Ferroelectric Electron Emitter

Ohwada

Nanataki

2007

jjap

A novel electron emitter utilizing the characteristics of ferroelectric ceramic materials has been developed. The electronemitting portion of the electron emitter has a unique microstructure that has a vacuum gap between the upper electrode and the surface of the ferroelectric layer. We confirmed electron emission by a three-step process that consists of (the first step) electron charge, (the second step) charge retention, and (the third step) electron emission. The asymmetric property of ferroelectric hysteresis in the process indicates the following results. In the first step, an electron charge is performed in synchrony with the polarization reversal of the ferroelectric layer. On the other hand, in the third step, the electric field in the vacuum gap advances the electron emission while the polarization reversal is performed in the ferroelectric layer.