| In the area of developing low voltage phosphors for field-emission displays, research has gained momentum over the last few decades. Many II-VI compound semiconductors with luminescence at various wavelengths in the visible spectrum make good candidates for display device applications, but do not meet the low excitation voltage requirement, An investigation conducted at Texas A&M University to achieve blue luminescence from zinc oxide showed that tungsten doped zinc oxide (W: ZnO) emits blue light with excitation voltage as low as 75 V. However, the source of this luminescence behavior was not identified. The research conducted to study this phosphor required fabrication of the phosphor under varying conditions. Using co-deposition technique, films containing varying concentration of tungsten were annealed under varying levels of temperature, time and argon to oxygen concentrations. Luminescence measurements performed included determining emission wavelength, brightness and color coordinates. Material analysis of the phosphor was also performed to determine the source luminescence. Using X-ray diffraction and infrared spectrometer, formation of zinc tungstate in the phosphor was determined to be the source of luminescence near 493 nm. |
