學研合作計畫---新穎奈米技術製作高效率半導體發光元件(I)

Abstract

在本計畫中，我們將利用氮化鎵材料及新穎奈米技術製作高效率半導體發光元件，其中研究主軸可歸納為以下幾點研究重點： (1) 發展並製作室溫下電激發藍光面射型雷射。 (2) 利用光子晶體技術製作電激發光子晶體面射型雷射。 (3) 製作半導體微共振腔、奈米共振腔及奈米雷射元件。 (4) 利用奈米製程技術發展高效率氮化鎵發光二極體。 (5) 利用新穎基板成長技術以開發高品質氮化鎵磊晶材料及氮化鎵基板。 在第一項研究重點中，我們已成功達成國際上第一個低溫連續操作之電激發面射型雷射，因此在此研究領域上已具有國際競爭優勢，若能在此計畫期間內達成室溫下之連續操作電激發面射型雷射，此研究成果必然受到國際上的重視，亦會是此研究領域的重大突破。第二項光子晶體面射型雷射方面，由於我們的雷射結構同時具有DBR與光子晶體，可提供橫向與縱向的光子侷限，亦是我們實驗室所提出的獨特結構。第三項半導體微共振腔與奈米雷射方面，由於此元件結構與面射型雷射相似，因此基於我們實驗室目前的技術，十分適合進行此研究領域的探討。第四項高效率發光二極體方面，由於目前LCD背光與未來白光照明的需要，高效率高亮度的白光發光二極體將是未來光電產業的需求。而決定各種發光元件之特性將是仰賴高品質氮化鎵基板，因此如何提升基板品質以改善各項氮化鎵發光元件將是本計畫的第五項重點。計畫內容中，不但包括目前產業需求的氮化鎵發光二極體、深具應用潛力的電激發氮化鎵面射型雷射、電激發氮化鎵光子晶體雷射與奈米雷射，我們更與國際知名的史丹佛大學Prof. Fan與Prof. Yamamoto合作，亦與日本東京工業大學Prof. Iga與Prof. Koyama合作，因此此計畫研究內容不但具有產業上的需求效益，更可提前產出專利布局，具有國際上的競爭優勢。

In this proposal, we propose to develop high efficiency nitride-based light emitting devices by novel techniques. The specific objectives of this proposal include: (1) Fabrication, design and improvement of GaN-based vertical-cavity surface-emitting lasers (VCSELs) for room-temperature continuous-wave electrically pumped operation. (2) Fabrication, design, and improvement of GaN-based photonic crystal surface-emitting lasers (PCSELs) for continuous-wave electrically pumped operation. (3) Fabrication, design, and analysis of GaN-based microcavities, nanocavities, and nanolasers for the study of microcavity polaritons, polariton lasers, and thresholdless nanolasers. (4) Fabrication of high-efficiency GaN-based blue light-emitting diodes (LEDs) by using nano fabrication techniques and optimal design of active layer for improvement of internal and external quantum efficiency. (5) Fabrication of high-qualtiy GaN materials and substrates using nano fabrication techniques and MOCVD growh for improving the emission efficiency of GaN VCSELs, PCSELs, nanolasers, and LEDs. We have successfully demonstrated the world-first continuous-wave electrically pumped GaN VCSELs at low temperature recently. In the proposal we propose to achieve room-temperature electrically pumped GaN VCSELs. We have also demonstrated the room temperature lasing action of GaN-based PCSELs which include the DBR and photonic crystal structures. This unique PCSEL structure was first demonstrated by our research group. We will continue to develop GaN PCSELs for achieving current injection laser operation in this proposed effort. In addition we will further develop GaN microcavity, nanocavity, and nanolasers. We also will conduct the development of high-efficiency GaN LEDs by simultaneously improving the internal and external quantum efficiency. In order to enhance the performance efficiency and characteristics of all of the light emitting devices to be developed in this proposed effort, we will conduct research efforts to improve the crystal quality of the GaN materials and substrates using various novel nano techniques and growth methods. This proposed project includes not only the leading photonics technology research and development subjects but also the promising applications of the GaN VCSELs, PCSELs, and nanolasers for the photonics industry. Our proposed research effort will conduct in collaboration with Prof. Iga and Prof. Koyama of Tokyo Institute of Technology for the research of RT CW electrically pumped GaN VCSELs. Prof. Iga is the inventor of VCSELs and a world class expert in the research of VCSELs. The experience gained from Prof. Iga and Prof. Koyama on the GaAs-based VCSELs will be very useful for this effort and will ensure the successful outcome of this research effort. We will also collaborate with Prof. Yamamoto and Prof. Fan of Stanford University to establish the theoretical analysis of GaN microcavity and GaN PCSELs. In the third year of this project, we will transfer our technology to LITEON Technology Corporation who has signed the letter of intent for cooperation in the research topics including GaN VCSELs, PCSELs and LEDs. This proposed research project is expected to produce major breakthroughs in GaN-based light emitting devices including VCSELs, PCSELs, nanolasers, and LEDs. These accomplishments will enhance our international academic status and reputation. The technology developed in this proposed research will also benefit the photonics industry in our country.