CdSe量子点敏化对GaAs发光特性的影响

Effect of CdSe Quantum Dot Sensitization on GaAs Luminescence Characteristics

为了探究量子点敏化对GaAs衬底发光性能的影响,采用化学沉积法制备了CdSe量子点,将量子点沉积在GaAs衬底上进行敏化。采用X射线衍射测试确认物相,利用扫描电子显微镜对量子点的形貌进行表征,并通过荧光光谱测试对CdSe量子点敏化后的GaAs衬底样品与未敏化的样品进行对比。结果表明:所制备的CdSe量子点大小均匀,尺寸约为20 nm,且均匀地附着在GaAs衬底上,CdSe量子点/GaAs形成了Ⅱ型能带结构。量子点敏化使GaAs衬底表面的载流子浓度升高。通过荧光光谱测试对各发光峰的来源进行了分析。测试数据显示,与敏化前相比,敏化后的GaAs衬底带边发光增强了2.25倍,缺陷发光增强了3倍。

In this study, the effect of quantum dot(QD) sensitization on the luminescent properties of GaAs substrates is investigated by preparing CdSe quantum dots via the chemical deposition method and depositing the quantum dots on the GaAs substrates for sensitization. X-ray diffraction is used to confirm the phase, the QD morphology is characterized via scanning electron microscopy, and the sensitized GaAs substrates are compared with the unsensitized ones through fluorescence spectroscopy. Results show that the prepared CdSe quantum dots are uniform in size(approximately 20 nm) and uniformly adhere to the GaAs substrates. CdSe QD/GaAs forms a type-II band structure. Moreover, quantum dot sensitization increases the carrier concentration on the GaAs substrate surface. The source of each luminescence peak is analyzed via fluorescence spectroscopy. Results illustrate that the band-edge luminescence of the sensitized GaAs substrate is 2.25 times higher than that of the unsensitized GaAs substrate. Furthermore, the defect luminescence of the sensitized GaAs substrate is three times higher than that of the unsensitized GaAs substrate.