二六族化合物半導體塊材及奈米結構的成長與特性分析

Growth and Characterization of Bulk and Nanostructure of II-VI Compound Semiconductors

曾培淵(Pei-Yuan Tseng)

指導教授 ： 周武清

中原大學/理學院/應用物理研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200154

摘要

利用溫度梯度溶劑長晶法成長不同濃度的碲化鋅鎘晶體，藉由光激螢光譜實驗研究光學特性。其近能隙光激螢光譜的半高寬最窄可達11毫電子伏特，而缺陷輻射密度最低為0.020，並且利用聲學聲子、縱向光學聲子及雜質等與激子作用的參數來擬合隨著溫度變化之光激螢光譜線寬。
除了碲化鋅鎘晶體外，利用分子束磊晶系統在擁有200 奈米硒化鋅緩衝層的砷化鎵基板上成長自聚性碲化鋅量子點的結構，並藉由原子力顯微鏡研究結構的表面形貌。觀察到大小尺寸不同的兩種量子點結構，其分布密度分別接近每平分方公分108和109個，並定義出碲化鋅量子點為三維的Volmer-Weber成長模式。較大尺寸量子點其第二型能帶間的光學躍遷造成強的光激螢光訊號，可以在1.9到2.2電子伏特間觀察到，而較小尺寸的碲化鋅量子點其螢光訊號可以在2.26電子伏特附近觀察到。

關鍵字

碲化鋅鎘 ； 量子點 ； 塊材 ； 碲化鋅 ； 奈米結構

並列摘要

Cd1-xZnxTe crystals were grown by the temperature gradient solution growth (TGSG). Optical properties of the Cd1-xZnxTe crystals were investigated by the photoluminescence (PL) spectroscopy. The full width at half maximum (FWHM) of 11 meV for the near band edge photoluminescence was obtained. The temperature dependent broadening of the photoluminescence line-width was fitted by the acoustic phonon, longitudinal optical phonon, and impurity interaction parameters. The defect radiative density is as low as 0.02.
In addition to the Cd1-xZnxTe crystals, self-assembled ZnTe quantum dot structures were grown on the GaAs substrates with the ZnSe buffer layer of 200 nm by the molecular beam epitaxy (MBE). Surface morphology was studied by the atomic force microscopy (AFM). A three-dimensional Volmer-Weber growth mode was identified. Two types of dots were observed. Strong photoluminescence observed at 1.9-2.2 eV was attributed to the emission from the type II ZnTe quantum dots with larger size. While, emission from the smaller ZnTe quantum dots is observed at an energy around 2.26 eV. The density of the larger and smaller dots was approximately 108/cm2 and 109/cm2, respectively.

並列關鍵字

Nanostructure ； CdZnTe ； bulk ； Quantum dot ； ZnTe

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