氮化銦及高銦組成氮化銦鎵奈米粒之微米及奈米尺度光學特性分析

Abstract

近年來三五族化合物半導體已成為發展光電產業中，最重要的材料。其中透過氮化銦與氮化 鎵所合成的氮化銦鎵，其發光波段控制在紫外到藍綠光的範圍中，更是目前應用在雷射發光二極 體與雷射二極體上最主要的材料之ㄧ。為了將發光波段延伸到紅光及紅外光，研發高銦含量的 氮 化 銦 鎵 及 氮 化 銦 成 為 熱 門 的 課 題 。 本 研 究 團 隊 最 近 特 別 研 發 流 量 調 製 磊 晶 法 (Flow Rate Modulation Epitaxy, FME)，成功利用 MOCVD 成長出氮化銦奈米粒，其發光位置在 0.75 eV 附近，半高寬甚至可下降至 50 meV，利用氮化銦的長晶參數，進而成長出一系列高銦組 成的氮化銦鎵奈米粒 (銦組成高於 60 %)。 透過初步觀測，發現不論是氮化銦或是高銦組成氮化銦鎵奈米粒，其表面除了會呈現不同形 貌的奈米粒外，也可發現微結構的特徵。本計劃將利用螢光光譜、拉曼光譜與近場光譜探討氮化 銦及高銦組成氮化銦鎵奈米粒的光學特性，包含時析載子傳輸機制、奈米粒應力變化情況與形貌 跟光譜的對應關係。 因此，針對上述計畫背景及目的所提，本計畫將細分為下列幾個主要的研究目標與方向，玆 條列如下： (1) 微米級(Micro)空間解析之氮化銦/高銦組成氮化銦鎵奈米結構之螢光光譜性： 搭配雷射定位技術，透過變溫光譜量測、時間解析光譜，分析微米區域內不同奈米結構 的載子傳輸機制、載子生命期....等特性。 (2) 微米級(Micro)空間解析之氮化銦/高銦組成氮化銦鎵奈米結構之拉曼光譜特性： 搭配雷射定位技術，分析微米區域內不同奈米結構中，應力變化情形…等特性。 (3) 奈米級(Nano)空間解析之氮化銦/高銦組成氮化銦鎵奈米結構之近場光譜特性： 偵測奈米結構內的光譜與形貌之對應關係。

Group-III Nitrides have become the most promising materials for a variety of optoelectronic devices in recent years. Of particular importance are heterostructures incorporating ternary InGaN alloys, which have been used as active materials in commercial light-emitting diodes (LEDs) and laser diodes operating in the ultraviolet and blue-green spectral ranges. It is the popular issue to study the In-rich InGaN and InN to extend the spectra range to red and infrared regions. Our team recently developed the flow rate modulation epitaxy (FME) method and deposited the InN nanodots successfully by MOCVD. The PL peak energy of InN nanodots was around 0.75 eV and the full width at half maximum (FWHM) could reduced to around 50 meV. Using the growth parameters of InN, we have grown a series of In-rich InGaN nanodots with In composition higher than 60 %. Through the preliminary observation, we found the existence of different shapes of nanodots or micro structures on the InN or In-rich InGaN. In this proposal, we plan to study the optical properties of InN and In-rich InGaN nanodots using optical measurement techniques to examine the mechanism of carrier transport、strain effect on nanodots and correspondence between surface morphology and spectra. The proposed subjects are listed below: 1. Micro-Photoluminescence spectra for studying spatial-resolved optical properties of InN and In-rich InGaN nanostructures： Using laser positioning、temperature dependent PL and time resolved PL to study the mechanism of carrier transport and carrier lifetime in the region of micrometer size. 2. Micro-Raman spectra for studying spatial-resolved optical properties of InN and In-rich InGaN nanostructures. Using laser positioning to study the strain effects on different nanostructures in the region of micrometer size. 3. Near-field scanning optical microscopy for studying spatial-resolved optical properties of InN and In-rich InGaN nanostructures. Study the correspondence between surface morphology and spectra in nanostructure.