Properties of patterned sapphire substrate embedded silver nanoparticles

• Main Authors: Wen-Fang Tsai, 蔡文芳
• Other Authors: Lung-Chien Chen
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/s4r572

碩士 === 國立臺北科技大學 === 光電工程系研究所 === 100 === GaN-based blue and green light emitting diodes (LEDs) grown on sapphire substrate are already commercially available. However, the improvement of output power is one of the most important issues for GaN-based LEDs application. In this study, the template was made by silver nanoparticle and pattern sapphire substrate improves the light power of GaN-based LEDs. In the beginning, sapphire was first etched by high temperature sulfuric acid, which later produced [Al(SO4)、Al(SO4)3‧17H2O]. This reactant was used as the etching mask, which later matched the two-section wet etching method of high temperature phosphoric acid to remove the mask layer. A single-layer silver film was deposited by RF magnetron sputtering on a pattern sapphire substrate. Annealing methods were also used to make silver film aggregate and form into silver nanoparticle. Then under different annealing temperature and time conditions, surface morphology and light characteristics of silver nanoparticle were also observed. Experiments proved that as annealing temperature and annealing time increased, reflection rate of incident light became smaller, due to the aggregation of silver nanoparticle. When annealed at 400℃ for 20 min in vacuum, can enable the light intensity of traditional LED increase about 2.58 times. Etching depth of the pattern sapphire substrate embedded with silver nanoparticle, on the other hand, also has something to do with LED light power. The reason of this improvement might be attributed to the reason that etching depth gave photon more opportunity to contact silver nanoparticle which created reflection and scattering light. At maximum, it can make traditional LED increase 2.28 times.