尖端晶體材料製備與分析核心設施計畫-子計畫三:尖端磁性半導體開發平台運作及自旋光電子物理研究

Abstract

本計畫主要整合國科會「尖端晶體材料製備與分析核心設施計畫」所支助的磁性半導體磊晶核心設施及貴重儀器計畫所支助交大且由物理領域管理的貴重儀器(1)球面像差修正掃描穿透式電子顯微鏡、(2)低溫陰極螢光分析系統、(3)X光繞射儀及(4)超導量子干涉儀，整合資源給國內外的學者使用，期望與國內外的學者研究新穎的自旋光電物理，創造優秀研究成果。 研究主題包括以電漿輔助分子束磊晶技術於藍寶石與矽基板上成長自聚性氧化鋅奈米柱，配合螢光光譜在近能隙邊緣觀察到的能帶分裂，分析奈米柱磊晶成長的應力變化，開發低缺陷密度與無應變的氧化鋅覆蓋磊晶層。更進一步在覆蓋磊晶層上繼續成長稀磁性氧化錳鋅量子點，俾克服基板引致的缺陷與應力的影響，研究量子效應下的光學與自旋特性，以及量子點在型貌變化與摻雜下所產生的應變對於光學與自旋特性的影響。也計畫藉由單晶Si3N4與氧化鋅奈米柱做為緩衝層，於矽基板(111)上成長高品質氧化鋅薄膜。進一步以三五族元素共摻雜法研製正型(p-type)氧化鋅薄膜，試圖提升氮摻雜於氧化鋅薄膜中的溶解度，提升正型氧化鋅薄膜之電性並找出最佳化薄膜製程條件。另外也成長一系列高度不匹配的二六族氧碲化(錳)鋅半導體薄膜，使用光調製反射譜、光激螢光頻譜、磁光頻譜、時間解析光譜和拉曼光譜，徹底研究高度不匹配氧碲化(錳)鋅半導體特殊之光電物理特性。研究的重點包括能隙彎曲、中間能帶的形成、複雜的載子動力學、磁光特性、晶格力學和晶體特性隨氧(錳)濃度變化的趨勢。

The main focus of this proposal is to integrate the resources of the core facility for magnetic semiconductor epitaxy, CSTEM, low temperature cathodo-luminescence analysis system, X-Ray, and SQUID for providing oversea and domestic scientists studying the physics of photonics and spintronics. The research topics include the growth of self-assembled ZnO nanorods on sapphire and Si substrate by plasma-enhanced molecular beam epitaxy and the overgrowth of ZnO layer on these nanorods. We expect to achieve low-defect and strain-free ZnO layers. The splitting of energy bands near band edge, which provides a comprehensive investigation on the strain evolution, can be used to analyze the growth dynamics of ZnO nanorods. Additionally, high quality ZnMnO quantum dots will be grown on the ZnO layer to study further the spin-physics of ZnO. We also plan to grow high quality ZnO films on Si(111) substrates by using single crystalline Si3N4 and ZnO nanorods as buffer layers. Using co-doping methods with both III-group and V-group elements, we try to achieve p-type ZnO films, increasing the solubility of nitrogen in ZnO, and enhancing the electrical properties of p-type ZnO films. Furthermore, a series of II-VI highly mismatched Zn1-yMnyOxTe1-x semiconductor films will be grown. The photomodulated reflectance, photoluminescence (PL), magneto PL, time-resolved PL, and Raman scattering will be adopted to investigate thoroughly the unique optoelectronic properties of highly mismatched Zn1-yMnyOxTe1-x alloys. This study will concentrate on the band-gap bowing, the formation of an intermediate band, the complex carrier dynamics, the magneto-optic characteristics, the lattice dynamics, and the crystalline properties as functions of oxygen and manganese concentrations.