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We deposited high quality ZnO film by electrophoretic deposition (EPD) using high quality ZnO powder prepared by solid-state pyrolytic reaction. X-ray photoelectron spectroscopy (XPS) and the infrared (IR) absorption spectrum clearly indicate that the ZnO phase powder has been prepared. Transmission electron microscope (TEM) imaging and x-ray diffraction (XRD) show that the average grain size of the powder is about 20nm. XRD and selected-area electron diffraction (SAED) reveal that the ZnO film has a polycrystalline hexagonal wurtzite structure. Only a strong ultraviolet emission peak at 390nm can be observed at room temperature. 相似文献
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磁控溅射方法生长的氮氧锌薄膜的光学特性 总被引:1,自引:1,他引:0
氧化锌(ZnO)是一种具有六方结构的宽禁带Ⅱ--Ⅵ族半导体材料,室温下能带带隙Eg为3.37eV。由于氧化锌在室温条件下具有较高的激子束缚能(60meV),保证了其在室温下较强的激子发光。此外氧化锌还具有较高的热稳定性和抗化学腐蚀特性,因而被认为是制作紫外半导体激光器的合适材料。自1997年首次发现ZnO室温紫外受激发射以来,ZnO已成为继GaN之后紫外发射材料的又一研究热点。但是,目前对于p型氧化锌及其发光器件的研究仍处于探索阶段,对其光电特性的研究仍需要更多投入。本文利用磁控溅射方法制备出氮氧锌薄膜样品,并通过在氧气气氛下退火处理,改变薄膜样品中氮的含量。通过X射线衍射谱、X射线光电子能谱、光致发光谱及喇曼光谱的测试,研究了氮在氧化锌薄膜中的含量变化以及氮对氧化锌薄膜的结构和光学特性的影响。 相似文献
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Temperature-Dependent Photoluminescence in Coupling Structures of CdSe Quantum Dots and a ZnCdSe Quantum Well
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A coupling structure of CdSe quantum dots (QDs) and a ZnCdSe quantum well (QW) is fabricated by using the molecular-beam epitaxy technique. The effect o~ temperature on the photoluminescence (PL) of the structure is studied. The results reveal that the activation energy of exciton dissociation in the coupling QDs/QW structure is much higher than that of simple CdSe QDs, which is attributed to the exciton tunnelling from the QW to QDs through a thin ZnSe barrier layer. The results also reveal that the position and width of the emission band of the QDs vary discontinuously at certain temperatures. This phenomenon is explained by the QD ionization and exciton tunnelling from the QW to the QDs. It is demonstrated that the coupling structure significantly improves the PL intensity of CdSe QDs. 相似文献
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Optical Properties of ZnCdSe/ZnMgSe Multiple Quantum Wells Grown by Molecular Beam Epitaxy
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We study the optical properties of ZnCdSe/ZnMgSe multiple quantum wells using photoluminescence (PL) and Raman scattering spectra.In the PL spectra,an intense emission band coming from the free exciton luminescence of the quantum wells can be observed from 80K to 300K.The exciton binding energy is eveluated by the dependence of PL intensity on the temperature,showing the behaviour of the better two-dimensional excitons.The result indicates that the enhancement of the confinement effect is due to containing Mg in the barrier layers.At room temperature,Raman scattering spectra are classified into confined optical modes and folded optical modes.This confirms the formation of a multilayer system with a higher crystalline quality. 相似文献
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采用化学气相法分别在石英舟内表面和单晶硅衬底上制备了ZnO微米片、纳米线、微米四足体以及微米球4种结构,并制作了相应的气敏传感器。扫描电子显微镜、气敏测试仪等结果显示:合成的ZnO纳米/微米结构尺寸在200 nm~100 μm之间,传感器最佳工作电流区间为120~130 mA,其中微米四足体制备的传感器灵敏度高达127,展现出优异的气敏特性。在4种结构中,微米四足体材料内部的VO缺陷含量最高,结合气敏测试与荧光光谱结果,我们认为材料内部的VO缺陷含量是影响材料气敏特性的最重要因素。 相似文献
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本文通过常压MOCVD方法,利用NH3气作为受主掺杂源,在(100)方向的GaAs衬底上生长了ZnSe:N膜。通过测量77K温度下光致发光光谱。观测到了由于掺氮引起的自由到束缚发射(FA)和深中心复合(SA).在低掺杂浓度下FA起主要作用,随着NH3气浓度增加,FA和SA带的强度随之增强,在重掺杂下SA带成为主要,同时带的半宽度展宽。室温下霍尔测量的结果表明。低掺杂浓度下ZnSe:N膜呈高阻态,而在高掺杂浓度下外延膜呈现P型电导,载流子浓度P~1016cm3.利用p-ZnSe/n-GaAs构成异质pn结,观测到了二极管的整流特性,进一步证实p型ZnSe的实现。 相似文献