國立臺灣大學應用力學研究所郭茂坤2006-07-262018-06-292006-07-262018-06-292005-07-31http://ntur.lib.ntu.edu.tw//handle/246246/21736半導體元件的光電特性決定於元件 的能帶結構，而量子點中磊晶層之應變 將造成半導體導電帶特徵能量的改變， 進而影響電子躍遷難易度。本年度計畫 以有限元素法套裝軟體分析砷化銦/砷化 鎵自組式量子點( InAs/GaAs selfassembled quantum dot)，因晶格不匹配 所引致的應變場，進而探討應變場對導 電帶的特徵能量與電子機率密度函數分 佈之影響。本研究以線彈性力學與初始 應力理論利用FEMLAB，配合真實製程 之模擬流程估算量子點內的應變分佈， 再將應變效應加入薛丁格方程式，同樣 以有限元素法予以分析。並澄清該系列 文獻對應變的定義，同時發現考慮砷化 銦鎵量子點中的銦之濃度後，模擬的應 變場與實驗結果十分吻合;亦即對於應 變場模擬而言，量子點中的銦之濃度為 不可忽略的因素。 本計畫考慮材料之異向性並將應變 場效應，藉由變形勢能，加入薛丁格方 程式中，而同樣以有限元素法予以分 析，藉此評估應變效應對於導電帶的特 徵能量與電子機率密度函數分佈之影 響，進而得到能帶間的躍遷能量(1.1 ~ 0.84 eV)與發光波長(1.13 ~ 1.48μm)。In this year’s project, the models based on linear elasticity and initial stress theory are successfully developed to evaluate the strain fields in the InAs/GaAs quantum dot nanostructures. The lattice mismatch in heterostructures induce the initial stress in quantum dots, and it will further lead to elastic deformation which calculated by finite element package—FEMLAB. The Schrödinger equation, including the strain-induced potential is also solved by finite element method. The solutions consist of the eigenenergy and the probability density function of the conduction band. The material properties of InGaAs quantum dots are assumed to depend on indium concentrations (c(x,z) ). The strain distributions obtained by using the FEM have good agreement with experimentally data through HREM imaging. Our results show that the energies of interband transitions and emission light’s wavelength are 1.1 ~ 0.84 eV and 1.13 ~ 1.48μm, respectively.application/pdf2453550 bytesapplication/pdfzh-TW國立臺灣大學應用力學研究所自組式量子點應變場有限 元素法薛丁格方程式Self-assembled quantum dotStrain fieldFEMSchrödinger equationreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/21736/1/932212E002015.pdf