电场调制下单量子阱ZnCdSe／ZnSe的激射行为研究

近年来,随着宽禁带Ⅱ－Ⅵ族半导体激光器取得突破性进展［１］,对ＺｎＳｅ基超晶格与量子阱的受激发射也进行了广泛的研究［２,３］,同时对电场调制下的ＺｎＳｅ基超晶格的受激发射也有过报导［４］．但对于电场调制下的ＺｎＣｄＳｅ／ＺｎＳｅ基单量子阱的激射行为研...     

Ⅱ—Ⅵ族半导体研究概观

回顾了Ⅱ－Ⅵ族半导体材料的研究状况。结合国际上的最新研究动态，总结出Ⅱ－Ⅵ族半导体材料研究的主要方向：（１）ｐ型掺杂研究；（２）ｐ型Ⅱ－Ⅵ族半导体的欧姆接触；（３）Ⅱ－Ⅵ族外延结构中的电子，激子增益；（４）量子线，量子点及稀磁半导体。     

Ⅱ－Ⅵ族半导体研究概观

回顾了Ⅱ－Ⅵ族半导体材料的研究状况．结合国际上的最新研究动态，总结出Ⅱ－Ⅵ族半导体材料研究的主要方向：（１）ｐ型掺杂研究；（２）ｐ型Ⅱ－Ⅵ族半导体的欧姆接触；（３）Ⅱ－Ⅵ族外延结构中的电子、激子与增益；（４）量子线、量子点及稀磁半导体。     

ZnSe0.93Te0.07-ZnSe多量子阱的光泵受激发射

宽带Ⅱ-Ⅵ族化合物半导体在短波长可见光范围内优越的发光特性使其在器件的研制方面有着广阔的前景.ZnSe基量子阱和超晶格结构,尤其是ZnCdSe-ZnSe量子阱已经在器件的制备方面取得了可喜的进展,因而人们研究的比较多.     

电场调制下Zn0.85Cd0.15Se-Znse应变层超晶格的受激发射

近几年,随着I-Ⅵ矶族宽禁带半导体二极管激光器取得突破性进展[1],对ZnSe基量子阱和超晶格结构的受激发射已进行了广泛的研究[2~3].但是迄今为止,人们尚未观测到电场调制下的受激发射增强现象.本文报道我们在Zn0.85Cd0.15Se-Znse应变层超晶格中观测到的电场调制的受激发射.     

高组分稀磁半导体Cd1-xMnxTe/CdTe超晶格的荧光谱研究

报道用分子束外延(MBE)技术生长的x=0.4,0.8的高组分稀磁半导体Cd1-xMnxTe/CdTe超晶格低温和室温荧光谱研究结果.基态激子跃迁能级荧光谱实验结果显示高组分超晶格中具有高量子效率和高质量光发射.对激子能级随温度的变化进行了详细研究,给出激子跃迁能量的温度系数.激子能级线型的展宽随温度变化关系可用激子-纵向光学声子耦合模型解释.与光调制反射谱实验结果进行了比较.     

量子点单光子源及其制备方法研究进展

本文概述了量子保密通讯中面临的三大关键技术。并对关键技术之一的单光子源技术进行了重点介绍，如量子点作为单光子源的研究概况，单光子发射的实现、激子跃迁、双激子跃迁引起的聚束和反聚束效应和光子相关测量等。并介绍了国际上制备半导体自组装量子点在形貌、发光谱、极化以及近场光学用于量子点极化和激子发射等研究方面所取得的进展。     

Ⅱ-Ⅵ族半导体激光器的新材料——ZnO量子点

介绍了研制Ⅱ－Ⅵ族半导体激光器方面的一个新途径－－自组织生长ＺｎＯ量子点微晶结构、ＺｎＯ已经实现了室温下光泵激发的受激发射,它将是继Ⅱ－Ⅵ族硒化物、Ⅲ－Ⅴ经物之后的又一种半导体激光器材料。     

纳米结构ZnO晶体薄膜室温紫外激光发射

文章综述了纳米结构的氧化锌半导体薄膜在室温下自由激子的自发辐射以及由自由激子引起的受激发射的特性，阐述了在不同激发密度下室温紫外受激发射的机理．纳米结构氧化锌半导体薄膜是用激光分子束外延(L-MBE)技术生长在蓝宝石衬底上的．薄膜由密集而规则排列的纳米尺度的六角柱组成．这些纳米六角柱起着限制激子运动的作用，激子的量子尺寸效应，使激子的跃迁振子强度大幅度增强．同时六角柱之间的晶面组成了一个天然的激光谐振腔．室温下用三倍频的YAG脉冲激光激发，可从这些纳米结构的氧化锌薄膜中观测到很强的紫外激光发射．研究发现，在中等激发密度下，紫外受激发射是由于激子与激子间碰撞而引起的辐射复合．在高密度激发条件下，由于激子趋于离化，紫外受激发射主要由电子-空穴等离子体的辐射复合引起．由于纳米结构中激子的跃迁振子增强效应，在室温下测量到的光学增益高达320cm^-1，这比在同样条件下测量到的块状氧化锌晶体的光学增益要高一个量级以上．与传统的电子-空穴等离子体激光辐射相比，激子引起的受激发射可在较低的激发密度条件下实现．这在实际应用上很有价值．     

Zno纳米晶的室温紫外受激发射特征

ZnO的激子特性对制备氧化锌基的光电子器件至关霞要,因此对ZnO量子点中激子的发光性质及其跃迁过程进行研究显得十分必要.采用溶胶-凝胶法制备了ZnO纳米晶,X射线衍射(XRD)结果表明样品具有六角纤锌矿多晶结构.研究了在不同泵浦功率激发下ZnO纳米晶的紫外发射的时间积分光谱和时间分辨光谱,观察到自南激子发光,激子-激子碰撞和电子-空穴等离子体引起的受激发射,研究了在不同泵浦功率激发下自由激子及激子-激子碰撞随泵浦功率依赖的动力学过程.研究结果对理解激子带边发射有一定帮助,对ZnO材料在短波长半导体光电器件方面有潜在的应用价值.     

白光和红绿蓝光LED可调光源研制

为了提高LED光源色温和亮度的调节精度和准确度,结合色温由低向高变化时光色所呈现的渐变特点,提出了一种低色温白光LED灯珠、高色温白光LED灯珠加红绿蓝光LED灯珠补偿式调光的方法.将色温分成三个部分进行调节,每个部分选用不同的LED灯珠组合来进行调光.实验结果表明:不同组合情况下的LED光源的初始输出色温相对于目标值的偏差范围在1％以内;亮度可以在保证色温不变的情况下独立进行调节,初始输出值与目标值的偏差范围在1％以内;经过微调之后可以达到目标值;达到了色温和亮度独立调节的要求;光源发光稳定,不会因为长时间工作而影响调节精度.     

Visualization and interferometry for cylindrical and spherical sample tomography and profilometry

A technique combining image processing and laser interferometry for visualizing and detecting the deformation of transparent cylindrical and spherical sample is proposed. This deformation includes geometric deformation such as volume transition in profilometry and physical deformation such as refractive index change in tomography. Phase contour lines are used for quantitative analysis and graphical representation of the deformation. This method allows us to visually detect the spatial variation of the deformation field and to evaluate the test quality such as misalignment of optical system. A theoretical analysis using phase contour map to characterize the deformation field is described in detail. A method using phase contour map to qualify the interferometric test is proposed. Analysis of test examples is carried out. Suggestions on using phase contour line method to ameliorate test system design are finally discussed.     

Nonlocal potentials and their exact and approximate local and velocity-dependent equivalents

We show that good approximations to the exact equivalent local potential (ELP) and damping factor of a nonlocal Perey-Buck potential can be calculated in the partial wave WKB approximation of Horiuchi. The exact ELP and damping factor are obtained by means of a method previously given by one of us. We also confirm that an approximate ELP proposed by Bauhoff et al. is of comparable accuracy as the Horiuchi approximation. Thesel-dependent ELP's exhibit reduced attraction in the interior and provide a test for higher order WKB approximations. We subsequently obtain an equivalent velocity dependent potential (EVDP) which is even exactly wave function equivalent to the original nonlocal potential. This almost local potential, unlike the trivial equivalent local potential, is smooth and well-behaved and is therefore particularly useful in nuclear reactions where the off-shell behaviour of the potential is important.     

Quantum and Classical Disparity and Accord

Discrepancies and accords between quantum (QM) and classical mechanics (CM) related to expectation values and periods are generally found for both the harmonic oscillator (SHO) and a free particle in a box (FPB), which may apply generally. These indicate non-locality is expected throughout QM. The FPB energy states violate the Correspondence Principle. Previously unexpected accords are found and proven that 〈x ²〉 _CM =〈x ²〉 _QM and τ _CM =τ _QMb (beat period i.e. beats between the phases for adjoining energy states) for the SHO for all quantum numbers, n. However, for the FPB the beat periods differ at small n. It is shown that a particle’s velocity in an infinite square well varies, no matter how wide the box, nor how far the particle is from the walls. The quantum free particle variances share an indirect commonality with the Aharonov-Bohm and Aharonov-Casher effects in that there is a quantum action in the absence of a force. The concept of an “Expectation Value over a Partial Well Width” is introduced. This paper raises the question as to whether these inconsistencies are undetectable, or can be empirically ascertained. These inherent variances may need to be fixed, or nature is manifestly more non-classical than expected.     

Muonic and pionic L- and M-series in carbon and oxygen and the pionic 2p level shift and width of oxygen

Muonic and pionic X-rays of the L- and M-series in C and O have been measured with a Si(Li) detector in the energy range between 7 keV and 60 keV. The target consisted of mylar (C₅H₄O₂). Energies and intensities of 21 transitions have been determined. The strong interaction shift of the pionic 2p level in O was measured and found to be +4.1 ±2.3 eV. The measured width of this level is 11±6 eV. The measured yields have been compared with cascade calculations.     

Carriers and sideband pairs and their analogues in physics and Biology

This is a further development of the author's paper A Unified Theory of Biology and Physics. It is found that male and female in biology, as well as particle and antiparticle in physics, are analogues of symmetrical sideband pairs in communication theory. This gives a new point of view from which to investigate the significance and characteristics of these different paired entities.These findings are intimately related to the fact that there are two transform domains of representation of entities in all the cases involved. They are the somatic and the genetic domains in biology, the configuration domain and the domain of conserved observables in physics, and the time and frequency domains in communication.