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1.
本文中,发现在In_xGa_(1-x)As缓冲层上非故意掺杂的InyGa_(1-y)As/(Al)GaAs超晶格样品中存在着两个互相反向的自建电场区,一个位于样品表面,另一个位于In_xGa_(1-x)As缓冲层和超晶格界面.据此,合理地解释了样品的光伏测试结果,并对此类样品的MOCVD生长工艺给予指导.  相似文献   

2.
徐遵图  徐俊英 《物理学报》1998,47(6):945-951
用分子束外延生长了GaAs/AlGaAs双量子阱激光器结构样品,并对不同温度快速热退火导致量子阱组分无序即阱和垒中三族元素的扩散过程进行了实验和理论研究 。用光荧光技术测量退火样品的n=1量子阱能级跃迁峰值位置,结果表明退火前后样品量子阱能级位置发生蓝移,蓝移量随温度的提高而增大,对退火过程中GaAs/AlGaAs量子阱中三族元素的扩散过程中进行了理论分析,并与实验结果相比较,获得了不同退火温度下  相似文献   

3.
研究了退火条件和 In 组份对分子束外延生长的 In Ga As 量子点(分别以 Ga As或 Al Ga As 为基体)光学特性的影响。表明:量子点中 In 含量的增加将导致载流子的定域能增加和基态与激发态之间的能量间隔增大。采用垂直耦合的量子点及宽能带的 Al Ga As 基体可增强材料的热稳定性。以 Al Ga As 为基体的 In Ga As 量子点,高温后退火工艺 ( T= 830℃)可改善低温生长的 Al Ga As 层的质量,从而改善量子点激光器材料的质量。  相似文献   

4.
研究了低温下分子束外延生长GaAs样品的稳态和瞬态发光。从200℃生长的样品呆测到很弱但清晰可辨的稳态发光峰,峰的能量位置相对于体GaAs激光子峰有一定蓝移。  相似文献   

5.
汽─液─固相法生长GaAs/InAs量子点1995年4月,日本《固体物理》第30卷第399页发表的比留间健之等的文章介绍了汽-液-固相法生长的GaAs/InAs量子点及其光荧光蓝移现象。在以As终止的GaAs(111)面上真空蒸发约1nm的Au膜,加...  相似文献   

6.
刘学彦 《发光学报》1998,19(4):361-363
由于GaAs与AlAs晶格常数相近,GaAs晶格常数为0.56535nm,AlAs的晶格常数为0.56605nm,当固熔体中Al组份x值从0变到1时,晶格常数变化约为0.15%.因此,在GaAs衬底上生长Ga1-xAlxAs时,在界面处的失配位错少,...  相似文献   

7.
高功率808nm InGaAsP—GaAs分别限制结构的半导体激光器   总被引:1,自引:0,他引:1  
朱宝仁  张兴德 《光学学报》1997,17(12):614-1617
介绍了研究分别限制结构InGaAsP-GaAs半导体激光器所得到的最新成果。利用引进的俄国技术,基于量子阱结构的InGaAsP-GaAs激光器,可用短时间液相外延技术制造。在GaAs衬底上制成的InGaAsP-GaAs分别限制结构的激光器,主要参数如下:发射波入λ=808nm,阈值电流密度J=300A/cm^2,对于条宽ω=100μm的激光器,连续功率为1-2W。  相似文献   

8.
朱李安  高鸿楷 《光子学报》1997,26(11):1003-1006
用高分辨率多晶多反射X射线衍射仪进行衍射空间的二维扫描是目前非损伤性表生半导体材料质量的手段之一。不同质量的材料在二维衍射空间中的衍射图形状不同。本文以GaAS/AlGaAs为例,展示了如何利用X射线的二维衍射空间图的形状来定性地分析半导体单晶样品的宏观弯曲,微观倾斜,组分梯度,应变,弛豫以及平行于界面的连续性等问题。  相似文献   

9.
利用自组织生长InAs/GaAs量子点的垂直相关排列机制,生长了上下两层用6.5nmGaAs间隔的InAs结构、下层以InAs已经成岛,由于应力传递效应,上层InAs由二维生长向三维成岛生长的转变提前发生,临界厚度从1.7ML变成1.5ML,透射业微镜截面象显示形成上下两层高度差别很大的InAs量子点,但是由于两层量子点之间存在器存在强烈的电子耦合,光致发光谱中只有与含大量子点的InAs层相对应的  相似文献   

10.
刘哲 《发光快报》1995,(1):31-34
首次在(100)GaAs衬底上成功地生长出ZnGa2Se4外延薄膜。用分子束外延技术在100GaAs衬底上制备Ga2Se3/ZnSe异质结时,用540℃以上的温度生长出ZnGa2Se外延层。  相似文献   

11.
nmSiO2对聚合物光纤光栅封装材料的改性研究   总被引:3,自引:1,他引:2  
分析了刚性纳米粒子改性聚合物的原理,重点分析了nmSiO2/硅氧烷(硅橡胶)复合材料的改性机理,采用120号溶剂性汽油为分散剂,通过共混法制得nmSiO2—乙烯基硅氧烷、含氢硅氧烷硫化而成的复合材料,用AJ-Ⅲa型原子力显微镜分析研究了该材料的组团结构并测试了其力学性能,结果表明,硅氧烷橡胶改性后,材料的弹性模量增加了15.4%;拉伸强度增加了19.4%;扯断伸长率增加了30%,用改性后的硅氧烷聚合物材料封装光纤Bragg光栅(FBG)压力传感器,可有效改善封装材料与光纤光栅的耦联性能;通过粒子含量控制可以增韧增强硅氧烷,从而可制作变量程压力传感器,同时可以延长传感器的使用寿命,  相似文献   

12.
聚对苯撑亚乙烯/SiO2块状溶胶-凝胶非线性光学材料的研究   总被引:2,自引:0,他引:2  
我们制作了一种由π-共轭聚合物聚对苯撑亚乙烯(PPV)均匀掺杂SiO2的块状溶胶-凝胶材料,该材料具有良好的光学品质和光学加工性能。通过扫描隧道显微镜(STM),紫外-可见吸收光谱和付氏红外光谱(FTIR)等方法研究了它的非线性光学特性。在对材料进行的光学两波耦合实验中,观察到了非对称能量耦合现象,并对此进行了分析。从吸光度和两波耦合衍射效率两方面对比了含PMMA和不含PMMA的两批不同掺杂浓度的PPV/SiO2 sol-gel材料的不同特性。  相似文献   

13.
Tian&#  rui ZHAI&#  &#  &#  &#  &#  Da&#  he LIU&#  &#  &#  &#  &#  Xiang&#  dongZHANG&#  &#  &#  &#  &# 《Frontiers of Physics》2010,5(3):266
Although the investigation on photonic band gap materials has been done more than two decades, it is still a big challenge to fabricate three-dimensional photonic crystal (PC) possessing wide band gaps in visible range. In this article, we have reviewed recent progresses on fabricating the PC with low refractive index material in visible range. In contrast to the material with large refractive index, it is cheap to use low refractive index material in fabricating the PC and will be greatly beneficial for future industrial productions. The holographic method to fabricate such a PC has been introduced, applying it to the design of the microlaser has also been discussed.  相似文献   

14.
The effect of an electrode material on electrical properties of a composite material based on super-high-molecular polyethylene (SHMPE) filled with carbon nanotubes has been studied using impedance spectroscopy. Using the method of replacing the sample by an equivalent electric circuit, it has been found that, depending on the electrode material, a blocking barrier with high active resistance and a space charge region adjacent to it arise in the interface region. It has been shown that the barrier height is controlled by surface electronic states of SHMPE and weakly depends on the electron work function of metal electrodes (Bardeen barrier). The characteristic times of electrical relaxation characterizing bulk and interface regions of the composite under study have been determined.  相似文献   

15.
The kinetics of fracture and deformation of the standard aluminum alloy AD1 and a similar alloy subjected to severe plastic deformation by high-pressure torsion under conditions of high-speed erosion has been investigated. It has been shown that, with an increase in the loading rate, the fraction of the brittle component on the fracture surface of the standard material, as well as the thickness of the damaged layer, increases more significantly than that for the material after the severe plastic deformation by high-pressure torsion. A relationship of the surface roughness of the material after the erosion with the loading rate and the thickness of the erosion-damaged layer has been established.  相似文献   

16.
本文介绍了几个学科互渗交叉,而得到深入发展的驻极体材料的研究历史、发展和未来的动向.特别指出了驻极态的研究是一个具有共性的基础理论课题.本文又特别介绍了驻极体(具有驻极态特性的材料)用于伪装材料方面的实践和未来发展方向,以及开发伪装(隐身)材料的意义.  相似文献   

17.
The process of commercial cement grinding in a helium atmosphere has been investigated in comparison with the process in an air atmosphere. Raw material particles have been sorted by sizes. Curves of helium release from the raw material after its grinding in air and in helium in the temperature range T = 20–1200°C have been constructed and analyzed. The influence of the character of water molecule adsorption on raw material cement particles before and after grinding in air and in helium and on the shape of helium release curves has been revealed.  相似文献   

18.
Although the investigation on photonic band gap materials has been done more than two decades, it is still a big challenge to fabricate three-dimensional photonic crystal (PC) possessing wide band gaps in visible range. In this article, we have reviewed recent progresses on fabricating the PC with low refractive index material in visible range. In contrast to the material with large refractive index, it is cheap to use low refractive index material in fabricating the PC and will be greatly beneficial for future industrial productions. The holographic method to fabricate such a PC has been introduced, applying it to the design of the microlaser has also been discussed.  相似文献   

19.
 用数值模拟的方法研究了FTO客体材料的线吸收系数随着穿透材料深度的变化关系,并拟合出材料有效线吸收系数与厚度之间的函数表达式。研究结果表明,在闪光照相中X光能谱发生了硬化,并随着穿透材料深度的增加谱平均线吸收系数会随之减小。FTO客体中钨的平均有效线吸收系数0.838(4.53%)cm-1,铜的平均有效线吸收系数0.297(4.96%)cm-1,能谱效应对有效线吸收系数的影响小于5%。在图像重建中利用上述的线吸收系数能够反演出精度达5%的材料密度。  相似文献   

20.
Different forms of an electrically conductive polymer, an organic semiconductor, namely, polyaniline, have been synthesized and characterized. The magnetization curves of the obtained forms have been analyzed. It has been found that, in the oxidized form, the material exhibits a magnetic hysteresis at room temperature. For polyaniline without a special doping with magnetic additives, this result has been obtained for the first time. The possibility of controlling the magnetic properties of the material by means of chemical treatment at the post-polymerization stage has been demonstrated.  相似文献   

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