Back Light Unit (BLU) and Color Filter are the two key components for the perfect color display of Liquid Crystal
Display (LCD) device. LCD can not light actively itself, so a form of illumination, Back Light Unit is needed for its
display. The color filter which consists of RGB primary colors, is used to generate three basic colors for LCD display.
Traditional CCFL back light source has several disadvantages, while LED back light technology makes LCD obtain
quite higher display quality than the CCFL back light. LCD device based on LED back light owns promoted efficiency
of display. Moreover it can generate color gamut above 100% of the NTSC specification. Especially, we put forward an
idea of Color Filter-Less technology that we design a film which is patterned of red and green emitting phosphors, then
make it be excited by a blue light LED panel we fabricate, for its special emitting mechanism, this film can emit RGB
basic color, therefore replace the color filter of LCD device. This frame typically benefits for lighting uniformity and
provide pretty high light utilization ratio. Also simplifies back light structure thus cut down the expenses.
Hall effect, photoluminescence (PL), infrared absorption, deep level transient spectroscopy (DLTS), and Raman scattering have been used to study property and defects of ZnO single crystal grown by a chemical vapor transport method (CVT). As-grown ZnO is N type with free electron density of 10<sup>16</sup>-10<sup>17</sup>cm<sup>-3</sup>. It has a slight increase after 900°C annealing in oxygen ambient. The DLTS measurement revealed four deep level defects with energy at 0.30eV, 0.50eV, 0.68eV and 0.90eV in the as-grown ZnO sample, respectively. After the high temperature annealing, only the 0.5eV defect survive and has a concentration increase. PL results of the as-grown and annealed ZnO indicate that the well-known green emission disappear after the annealing. The result suggests a correlation between the 0.68eV defect and the green PL peak. Results of P-doped ZnO were also compared with the undoped ZnO sample. The nature of the defects and their influence on the material property have been discussed.