氧化鋅奈米柱陣列耦合侷域性銀奈米粒子表面電漿共振於氮化鎵藍光二極體效率提升之研究

Abstract

本論文是利用射頻磁控濺鍍系統濺鍍一層30nm的氧化鋅晶種層在氮化鎵發光二極體表面，再輔以水熱法濃度0.03M的六水合硝酸鋅(Zn(NO3)2．6H2O)和0.03M六亞甲基四胺(CH2)6．N4 (hexamethylenetetrami- ne,HMTA)的混合水溶液中成長氧化鋅奈米柱，最後再把銀奈米粒子用以旋轉塗佈(500 轉/ 40 秒)的方式塗佈進氧化鋅奈米柱之間，再放在真空乾燥盒內以70℃/ 10 分鐘加熱乾燥。

銀奈米粒子能吸收部分氮化鎵無法透射出去的光轉成表面電漿，之後再藉由氧化鋅奈米柱將表面電漿傳導出去，進而提升氮化鎵發光二極體的光電轉換效率、外部量子效率、電激發光譜強度以及光激發螢光光譜強度。

In this study, we use magnetron sputtering system to grow a 30 nm ZnO thin film on the surface of GaN-based light-emitting diodes (LEDs) as the seed layer. The ZnO nanorods arrays were then grown by hydrothermal method with 0.03 M (Zn(NO3)2．6H2O) and 0.03 M (CH2)6．N4 (hexamethylenetetrami- ne,HMTA) compounds in a solution at 110℃ for 1 hour duration. After that, we spin coated Ag nanoparticles into ZnO nanorods by 500 r.p.m / 40 sec and baked the sample in the box with vacuum for 10 mins.

The primary function of Ag nanoparticles is to absorb the wave-guided light trapping in the LED device, which consequently increases the localized field via surface plasma resonance (SPR) effect. The photoexcitated electrons in Ag nanopartilces jump from ground state to excited states, followed by relaxation of the excited electrons, accompanied by radiative emission which further enhaces the light output power and the exteranl quantum efficiency of the LEDs.