共查询到18条相似文献，搜索用时 31 毫秒
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本文将基于有效质量近似下的变分法,理论研究了纤锌矿InGaN/GaN staggered量子阱中的激子态和光学性质.数值结果显示了InGaN量子阱中的量子尺寸和staggered受限垒对束缚于量子阱中的激子态和光学性质有着明显的影响.当阱宽增加时,量子受限效应减弱,激子结合能降低,带间发光波长增加.另一方面,当量子阱中staggered受限势增加时,量子受限效应增强,激子结合能升高,带间发光波长降低.本文的理论结果证明了可以通过调节staggered垒高和量子尺寸来调控纤锌矿InGaN staggered量子阱中的激子态和光学性质. 相似文献
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用分子束外延在GaAs衬底上生长了CdSe/CdMnSe多量子阱结构.利用X射线衍射(XRD)、变密度激发的PL光谱、变温度PL光谱和变密度激发的ps时间分辨光谱研究了CdSe/CdMnSe多量子阱结构和激子复合特性.讨论了随温度升高辐射线宽展宽和辐射复合效率降低的机理.发现不同激发密度下发光衰减时间不同,认为它的机理可能是无辐射复合引起的.在该材料中观测到激子激子散射发射峰,它被变密度激发和变温度PL光谱所证实.关键词：CdSe/CdMnSe量子阱光学性质 相似文献
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本文先比较了几种常用方法(修正的无规元素等位移模型、虚晶近似和简化相干势近似等)对纤锌矿三元混晶体声子频率的拟合结果,再选用与实验数据接近的拟合方法,结合介电连续和单轴晶体模型导出含纤锌矿三元混晶InxGa1－xN和AlxGa1－xN单量子阱各类光学声子模的色散关系,进一步分析了声子模随组分的变化. 结果表明,修正的无规元素等位移模型对单模性纤锌矿 相似文献
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ZnSe／ZnS多量子阱激子光学双稳性 总被引：2，自引：0，他引：2
用MOCVD在CaF_2衬底上生长的ZnSe/ZnS多量子阱材料,在77K下用N_2激光泵浦染料获得的宽带光脉冲进行了非线性光学测量,首次观察到ZnSe/ZnS多量子阱的激子光学双稳性,据分析这是由激子的能带增宽效应引起的增强吸收光学双稳性. 相似文献
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采用多源有机分子气相沉积系统(OMBD)制备了Alq3,PBD/Alq3,PBD/Alq3/PBD单层、双层以及量子阱结构,利用电化学循环伏安法和吸收光谱、荧光光谱研究了量子阱的类型和样品的光致发光特性.电化学循环伏安法和吸收光谱的测量结果表明,PBD/Alq3有机量子阱为Ⅰ型量子阱结构.荧光光谱的研究结果表明,单层Alq3的光致发光峰不随Alq3厚度变化而变化;但是双层PBD/Alq3结构光致发光峰随Alq3厚度的减小而发生蓝移;同样对于PBD/Alq3/PBD量子阱结构光致发光峰随Alq3厚度的减小而发生蓝移.对引起光谱蓝移的原因进行了讨论.关键词：有机量子阱光谱蓝移 相似文献
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采用光致发光谱、光致发光激发谱以及拉曼光谱对GaN基量子阱材料进行了实验观察和分析 .实验结果表明样品中量子点结构不均匀及InGaN层中In成分分布不均匀 ,且其光致发光谱的波峰是由自由激子辐射复合发光引起的 .同时由室温下InGaN/GaN量子阱的拉曼谱可得知InGaN/GaN多量子阱的结构特征 相似文献
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量子阱非线性光学研究进展 总被引：1，自引：0，他引：1
综述了量子阱非线性光学领域近年来实验工作的进展，重点介绍了共振增强的二阶和三阶非线性效应、光折变效应、量子阱光调制器和ＩＶ族材料的非线性过程，指出该领域发展迅速，应用前景十分广阔。 相似文献
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半导体量子阱及超晶格材料具有室温激子效应以及强的光学非线性从而得到人们广泛的重视。利用半导体量子阱和超晶格可以制备出高速度、低闭值、小尺寸及室温工作的半导体激光器、光双稳器件等一系列光电子器件. 相似文献
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通过对描述半导体激光器基本光波导方程的数值求解，分析了ＡｌＧａＡｓ／ＧａＡｓ分别限制量子阱激光器的光学限制特性，比较了不同缓变结构及多量子阱结构的光学限制因子。 相似文献
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Dmitry Sizov Rajaram Bhat Jerome Napierala Chad Gallinat Kechang Song Donald Allen Chung‐en Zah 《physica status solidi (a)》2010,207(6):1309-1312
Using varied stripe length method we systematically studied optical gain properties of blue‐green 3 nm InGaN QWs grown on c‐plane and (11−22) semipolar substrates. We determined that for such structures when the product of modal net gain at peak and stripe length exceeds factor 5 the gain saturation occurs due to depletion of pumped carriers. We then focused our attention on the gain in unsaturated conditions. We observed strong gain peak position blue shift with increase of pumping power for both substrate orientations due to quantum well state filling and for c‐plane due to piezoelectric field screening. Thus in order to increase lasing wavelength, minimizing optical losses, and maximizing modal gain are essential. We then found that for the semipolar QWs the gain at ∼500 nm was 2× higher with the stripe along [−1−123] direction despite the fact that at low pumping level the polarization switching of spontaneous emission resulted predominant E ||[−1−123]. Finally we compared the semipolar and c‐plane QWs and found that the gain increase with pumping power of c‐plane QW is slower than that for semipolar QW in high gain direction while the transparency pumping power is lower for c‐plane. 相似文献
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Undoped and Si-doped AlGaN/AlN multiple quantum wells(MQWs) were grown on AlN/Sapphire templates by metalorganic phase vapor epitaxy.High-resolution x-ray diffraction measurements showed the high interface quality of the MQWs little affected by Si-doping.Room-temperature(RT) cathodoluminescence measurements demonstrated a significant enhancement of the RT deep ultraviolet emission at about 240 nm from the AlGaN/AlN MQWs by Si doping.The mechanism of the improved emission efficiency was that the Si-doping partially screens the internal electric field and thus leads to the increase of the overlap between electron and hole wavefunctions.Further theoretical simulation also supports the above results. 相似文献
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F. Ungan 《Journal of luminescence》2011,131(11):2237-2243
In the present work, the changes in the intersubband optical absorption coefficients and the refractive index in a modulation-doped quantum well have been investigated theoretically. Within the envelope function approach and the effective mass approximation, the electronic structure of the quantum well is calculated from the self-consistent numerical solution of the coupled Schrödinger-Poisson equations. The analytical expressions of optical properties are obtained by using the compact density-matrix approach. The numerical results GaAs/AlxGa1−xAs are presented for typical modulation-doped quantum well system. The linear, third-order nonlinear and total absorption and refractive index changes depending on the doping concentration are investigated as a function of the incident optical intensity and structure parameters, such as quantum well width and stoichiometric ratio. The results show that the doping concentration, the structure parameters and the incident optical intensity have a great effect on the optical characteristics of these structures. 相似文献
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We present a UHV cathodoluminescence study of the spontaneous polarization field in polar [0001] and nonpolar GaN/GaInN single quantum well structures. Employing electron‐stimulated desorption a descreening of the spontaneous field in the polar c‐plane samples was observed, which counteracts the piezoelectric field in the quantum well. While in c‐plane samples a strong blueshift of the emission energy takes place and a drastic increase of emission intensity occurs, no change of the QW emission energy and intensity from m‐plane samples was detected. The different behaviour under the same experimental conditions can only be explained with the absence of the spontaneous polarization field in the nonpolar m‐direction. 相似文献
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A. Sa'ar Y. Lavon F.H. Julien P. Boucaud J. Wang J.-P. Leburton R. Planel 《Superlattices and Microstructures》1997,21(4):517-525
Mid-infrared optical emission due to intersubband transitions between excited conduction subbands of a coupled quantum well structure is studied. The emission process is based on optical pumping of free carriers from the ground subband into the third subband followed by a radiative transition from the third subband into the second subband and a fast phonon assisted relaxation into the ground subband. We have observed spontaneous emission at 14 μm that persists up to room temperature. Our results indicate that population inversion between conduction subbands and large stimulated gain can be achieved. 相似文献
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M. Tchernycheva L. Nevou L. Vivien F. H. Julien P. K. Kandaswamy E. Monroy A. Vardi G. Bahir 《physica status solidi b》2010,247(7):1622-1627
In this paper we review the recent achievements in terms of GaN/AlGaN‐based intersubband (ISB) physics and devices. We first discuss the design issues and in particular the band bending effect and its influence on the ISB absorption. We then illustrate recent achievements in terms of III‐nitride ISB devices with special emphasis on electro‐optical modulator and a quantum cascade detector operating in the near‐infrared. We show that these devices offer high frequency response at telecommunication wavelengths. 相似文献
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由于微制造技术的不断发展,如液相外延(LPE),气相外延(VPE),金属有机化学气相沉积(MOCVD)以及分子束外延技术(MBE)等先进的材料生长技术方法也日趋完善,从而使得各种低维半导体量子器件(如半导体、超晶格、量子阱、量子线和量子点等)制造日趋成熟.由于这些低维半导体量子器件具有很强的非线性光效应,而且随着材料、外形、尺寸等的不同,非线性光效应也有很大的差别,更由于其可能存在的广泛的应用前景,所以近年来,一直是人们研究的重点.近来,由于人们相信,利用GaAs/AlGaAs量子阱有可能制造出一些新型的光学仪器,如光开关、光限幅器、光调制器等,所以,对不同势形的GaAs/AlGaAs量子阱的非线性光学特性一直吸引着人们进行理论和实验的研究.而在最近几年,对双量子阱的研究也成为了人们的研究重点.通过密度矩阵和迭代的方法,得到双量子阱中的第一、第三阶子带光吸收表达式,我们将用一个典型的GaAs/AlGaAs双量子阱代入其中进行数值计算,并进行讨论.我们的计算结果显示,阱的光吸收峰不但与中间的势垒宽度有关,更与入射光强有关. 相似文献
18.
Alexander Polyakov Anatoliy Govorkov Nikolay Smirnov Alexander Markov In‐Hwan Lee Haeng‐Keun Ahn Sergey Karpov Stephen Pearton 《physica status solidi (a)》2010,207(6):1383-1385
Multi‐quantum well (MQW) GaN/InGaN structures prepared by epitaxial lateral overgrowth were characterized by various techniques to better understand the difference of the materials properties and heterostructure operation in the wing and window regions. Detailed interpretation of the characterization data is given, invoking quantum‐mechanical simulation of the grown heterostructures. 相似文献