Abstract
摘要：雖然近年來全球表面電漿子耦合發光二極體的研究愈受重視，一些相關的基本課題仍模糊不清，尤其不少期刊相關文章內出現錯誤或誤導的表面電漿子耦合基本觀念或結論。基於我們過去幾年製作表面電漿子耦合發光二極體研究經驗，於本計畫中我們將聚焦探討數個表面電漿子耦合發光二極體的基本課題。在上一個國科會補助計畫中，我們展示了數個表面電漿子耦合發光二極體的功能，包括：發光效率之提昇、偏振輸出的產生、加入介電質中間層來降低金屬損耗、效率滑降之減少等，尤其我們製作了金屬突出結構來提高表面電漿子耦合效果。此外我們也由理論模擬研究發現一些出乎預料的表面電漿子耦合行為，這些觀察使我們覺得這些表面電漿子耦合的基本課題有必要以實驗來重新詳加檢驗，因此於本計畫中我們將在發光二極體上製作不同幾何參數的金屬突出結構及表面奈米顆粒，以光致發螢光及電激發光之量測來探討數個基本課題，這些課題包括表面電漿子耦合強度或發光二極體發光效率提昇程度隨下列因素之變化：量子井內輻射電偶極之極化方向、量子井內激子形成及載子侷域化、表面電漿子共振模態(偶極子或高階共振)、金屬結構及量子井間之距離、元件之溫度等。本計畫專注於實驗研究，主持人將與另一專注類似課題理論模擬研究之計畫主持人密切合作，使得實驗結果可以獲得驗證及正確解讀。基於這些研究努力，我們期盼能澄清在國際上的一些錯誤或誤導之觀念，同時經由表面電漿子耦合之發光二極體其發光效率可以更加提昇。
Abstract: Although the research on surface plasmon (SP) coupled InGaN/GaN quantum-well (QW) light-emitting diode (LED) has attracted more and more attention in the recent years, quite a few fundamental issues are still unclear. In some journal publications, mistaken or misleading concepts or conclusions can be found. Based on their SP-coupled LED implementation research in the past few years, this research team will focus on the studies of several fundamental issues of SP-coupled LED in this project. In the last NSC-funded project, this team has demonstrated a few functions of SP-coupled LED, including the enhancement of emission efficiency, the generation of polarized output, the decrease of metal dissipation by inserting a dielectric layer at the metal/semiconductor interface, and the reduction of the efficiency droop effect. In particular, this team implemented a metal protrusion structure for generating effective SP coupling with the QWs of an LED. Also, theoretical/numerical studies demonstrated a few unexpected SP coupling behaviors, leading to the need of experimentally reevaluating those fundamental issues. In this project, this team will implement metal protrusions and surface metal nanoparticles of varied geometry on LEDs for investigating those fundamental issues based on photoluminescence and electroluminescence measurements. Those fundamental issues include the dependencies of SP coupling strength or emission enhancement on the orientation of radiating dipoles in the QW, the exciton formation and carrier localization in the QW, the mode pattern of SP resonance (dipole or higher-order SP resonance), the distance between the metal structure and the QW, and the device temperature. The principal investigator for experimental studies in this project will be closely cooperating with a colleague (submitting another proposal to NSC) for theoretical/numerical research on the similar issues such that the experimental results can be better interpreted. It is expected that based on the research results of this project, a few mistaken or misleading concepts can be clarified. Also, the SP coupling for enhancing LED efficiency can be more effective.
Keyword(s)
表面電漿子
發光二極體
量子井
金屬突出結構
金屬奈米顆粒
輻射電偶極
surface plasmon
light-emitting diode
quantum well
metal protrusion
metal nanoparticle
radiating dipole
