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Rapid Thermal Annealing Effects on Structural and Optical Properties of Self-Assembled InAs/GaAs Quantum Dots Capped by InAIAs/InGaAs Layers 下载免费PDF全文
Effects of rapid thermal annealing on the optical and structural properties of self-assembled InAs/GaAs quantum dots capped by the InAlAs/InGaAs combination layers are studied by photoluminescence and transmission electron microscopy. The photoluminescence measurement shows that the photoluminescence peak of the sample after 850℃ rapid thermal annealing is blue shifted with 370meV and the excitation peak intensity increases by a factor of about 2.7 after the rapid thermal annealing, which indicates that the InAs quantum dots have experienced an abnormal transformation during the annealing. The transmission electron microscopy shows that the quantum dots disappear and a new InAlGaAs single quantum well structure forms after the rapid thermal annealing treatment. The transformation mechanism is discussed. These abnormal optical properties are attributed to the structural transformation of these quantum dots into a single quantum well. 相似文献
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Effect of Misfit Dislocation Originated from Strained Layer on Photoluminescence Properties of InxGa1-xN/GaN Multiple Quantum Wells 下载免费PDF全文
Inx Ga1-x N/GaN multiple quantum well (MQW) samples with strain-layer thickness larger/less than the critical one are investigated by temperature-dependent photoluminescence and transmission electron microscopy, and double crystal x-ray diffraction. For the sample with the strained-layer thickness greater than the critical thickness, we observe a high density of threading dislocations generated at the MQW layers and extended to the cap layer. These dislocations result from relaxation of the strain layer when its thickness is beyond the critical thickness. For the sample with the strained-layer thickness greater than the critical thickness, temperature-dependent photoluminescence measurements give evidence that dislocations generated from the MQW layers due to strain relaxation are main reason of the poor photoluminescence property, and the dominating status change of the main peak with increasing temperature is attributed to the change of the radiative recombination from the areas including dislocations to the ones excluding dislocations. 相似文献
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通过简单的水热合成路线,在没有模板、表面活性剂的作用和未处理的基底上合成出铝掺杂ZnO 纳米盘,并以纳米盘为基底自组装合成了ZnO纳米棒阵列.扫描电镜(SEM)观察到铝掺杂ZnO纳米盘的厚度为 200 nm,纳米盘的尺寸约为2 μm;纳米棒的直径约为150 nm,长约1.5 μm.通过不同生长阶段的形貌变化探讨了ZnO纳米结构的形成机理,表明自组装过程存在两个成核阶段.另外, 研究了铝离子掺杂对样品光致发光性质的影响. 相似文献
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制备了3种不同形貌的Ti O2结构:纳米杯、(001)纳米片、(100)纳米片,并进一步与Pt纳米粒子复合以去除污水中的有机染料。透射电镜结果证实了3种Ti O2纳米结构的形成,观察到了附着其上的Pt纳米粒子。使用XRD确定了3种Ti O2纳米结构均为锐钛矿相。以罗丹明B作为有机染料,检测了不同形貌Ti O2及其Pt复合物的光催化性能。结果表明:纳米杯状的Pt/Ti O2在罗丹明B溶液中表现出最高降解率,在1.5 h内降解率可达99.1%。同时讨论了Ti O2及其复合物的光降解机理。 相似文献
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