Copper-doped zinc oxide nanowires were fabricated on copper-coated silicon substrate by sintering a mixture of zinc oxide and graphite powders at high temperature. Copper functioned as a catalyst in the zinc oxide nanowire growth and was incorporated during the growth as a dopant. The size of copper-doped zinc oxide nanowires ranges from 30 to 100 nm in diameter and tens to hundreds of microns in length. The photoluminescent excitation spectra showed multiple absorption peaks in the ultraviolet and blue/green region. Correspondingly, broad and continuous photoluminescence spectra were observed extending from the ultraviolet to the red region with shoulder peaks at room temperature, which is different from that of the bulk. The x-ray photoelectron spectroscopy and low temperature photoluminescence were employed to analyse the luminescent mechanism.

http://iopscience.iop.org/article/10.1088/0957-4484/15/7/026/pdf

Photoluminescent properties of copper-doped zinc oxide nanowires

Luminescent properties and lattice defects correlation on zinc oxide

Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles

Recent advances in the phosphors used for field emission displays (FEDs) are discussed. After reviewing the range of voltages and phosphors being used in first generation devices, the improved properties of future generation phosphors are reviewed. Specifically, next generation displays will require better low voltage efficiencies, chromaticity, saturation behavior, and maintenance. Possible routes to achieve these improvements are discussed. The improved understanding of the role of charging and surface recombination effects on cathodoluminescent intensity and efficiency is reviewed. An improved understanding of electron beam-stimulated surface chemical reaction effects on the degradation of phosphor is presented. It is concluded that recent research efforts have created a new level of understanding of FED phosphors, and this should lead to the necessary improvements in properties.

Advances in field emission displays phosphors

Nowadays there are several technologies used for flat panel displays (FPDs) and the development of FPDs with enhanced energy efficiency and improved display quality is strongly required. Field emission displays (FEDs) have been considered as one of the most promising next generation flat panel display technologies due to their excellent display performance and low energy consumption. For the development of FEDs, phosphors are irreplaceable components. In the past decade, the study of highly efficient low-voltage cathodoluminescent materials, namely FED phosphors, has become the focus of enhancing energy efficiency and realizing high-quality displays. This review summaries the recent progress in the chemical synthesis and improvement of novel, rare-earth and transition metal ions activated inorganic cathodoluminescent materials in powder and thin film forms. The discussion is focused on the modification of morphology, size, surface, composition and conductivity of phosphors and the corresponding effects on their cathodoluminescent properties. Special emphases are given to the selection of host and luminescent centers, the adjustment of emission colors through doping concentration optimization, energy transfer and mono- or co-doping activator ions, the improvement of chromaticity, color stability and color gamut as well as the saturation behavior and the degradation behavior of phosphors under the excitation of a low-voltage electron beam. Finally, the research prospects and future directions of FED phosphors are discussed with recommendations to facilitate the further study of new and highly efficient low-voltage cathodoluminescent materials.

Recent progress in low-voltage cathodoluminescent materials: synthesis, improvement and emission properties

Time-resolved spectroscopic study of energy transfer in ZnO:EuCl3 phosphors

In order to obtain the practical vacuum data in field emission display packages which are composed of very thin gapped glass plates, the effects of heating time and temperature as well as geometrical factors such as the gap size between the glass plates, the inner diameter, and length of the evacuation tube were investigated. Even though the evacuation system is in an ultrahigh vacuum of more than 1.0×10−7 Torr, the attained vacuum level with 55 mm×55 mm×1.1 mm panel was 3.0×10−5 Torr. The attainable vacuum level for the panel was calculated by considering conductance of the evacuation system. The calculated and measured values are consistent (2.8×10−5 and 3.0×10−5 Torr). Heating glass frit sealed packages do not improve vacuum level and H, H2O, CO, and CO2 were identified as impurities remaining inside of the panels.

Experimental and theoretical considerations on evacuation of vacuum package for field emission display

Abs trac t The vacuum levels were measured as a function of heating time and temperature and the geometrical factors such as the panel gap, lhe inside diameter of tube and the tube length and the analysis of the outgassing in package were investigated. The vacuum level of a panel 5 0 m n X 5 0 m m X l . l m m and attached the tube of @6 mm was 3.0X10'5 torr pumped for 90 minutes. I t was similar to the measured vacuum level. After heating the panel during pumping, the vacuum level was slightly improved to 2 . 8 X 1 0 5 torr. From a RGA analysis outgassing materials were proved to be H , HzO, CO and CO2 . The calculated vacuum level was 2.6X10-5 torr.

http://ieeexplore.ieee.org/iel3/4954/13634/00627681.pdf

Min-Gi Kwak

Papers

Time-resolved spectroscopic study of energy transfer in ZnO:EuCl3 phosphors

Experimental and theoretical considerations on evacuation of vacuum package for field emission display

Experimental and Theoretical Considerations on Evacuation of Vacuum Package for FED

Experimental and Theoretical Considerations on Evacuation of Vacuum Package for FED