Design and Fabrication of Light-Emitting Diodes for Backlight and Laser Printer Applications

• Main Authors: Chih-Chung Chen, 陳致中
• Other Authors: San-Liang Lee
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/65222926776839715955

碩士 === 國立臺灣科技大學 === 電子工程系 === 95 === This thesis includes two research topics. One is to fabricate edge-emitting light-emitting-diodes on a commercial GaN LED epi-wafer for using as line sources for fiber cloth or laser printing applications. Another is to employ two-dimensional photonic crystals on surface-emitting light-emitting-diode to lower the phenomenon of total internal reflection and enhance the external quantum efficiency by the effects of Bragg scattering. We design special Half-Moon waveguide structure for the edge-emitting devices in order to reduce the facet reflection. This can avoid the resonant effect. The measured device results indicate that most light is emitted from the edge-emitting end facets. Current devices have relatively low output power due to the high electrical and thermal resistance of the device structure where the thick substrate was not removed. This issue has to be overcome for improving the device performance in the future. By using the holographic exposure method, we fabricate SiO based photonic crystals on the surface of a LED wafer. From the PL measurement, we find that adding the photonic crystal structure can indeed change the radiation direction of output light and enhance the extraction efficiency.