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1.
对用原子层外延方法,在[001]晶向GaAs衬底上生长的[(Cdse)m(Znse)n]p-ZnSe应变量子阱结构,在10~300K温度范围内测量了喇曼散射光谱,观察到两种类ZnSeLO声子限制模.利用改变样品温度和入射光能量实现了共振喇曼散射,观察到高达7阶的类ZnSeLO声子模.并讨论了多声子喇曼散射和热萤光过程的区别.  相似文献   

2.
用分子束外延方法在GaAs(100)衬底上成功生长了高质量的Zn1-xMnxSe/ZnSe(x=0.16,x=0.14)超晶格结构,用X射线衍身 喇曼散射对其结构,应变分布以及光散射性能进行了研究,江超晶格的总厚度大于最度是格将完全弛豫至一个新的平衡晶格常数,此时在(100)平面,ZnSe阱层受到张应变,而Zn1-xMnxSe垒层受到压变应。从而,导致其喇曼光谱中,ZnSe Zn1-xMnxSe垒  相似文献   

3.
本文通过X射线双晶衍射和双晶摇摆曲线的计算机模拟方法研究了在Si(001)上生长的Ge0.5Si0.5/Si应变层超晶格的结构及其完整性,结果表明:在350-550℃的低温生长条件下,可生长出较高质量的超晶棺材料,并且在350℃时质量最好.在这些样品的生长过程中界面上产生了不同程度的失配位错,并与生长温度有关.周期厚度有4%以内的波动,层与层之间有轻微的混元,观察到了超晶格卫星衍射峰的分裂现象,并进行了讨论.  相似文献   

4.
本文采用泵浦-探测技术研究了ZnSe/ZnCdSe多量子阱室温激子饱和吸收,并根据K-K关系计算得到521.6nm至544nm的光学非线性折射率的变化.观测到由折射率变化引起的ZnSe/CdZnSe多量子阱光双稳器件的室温激子光双稳.根据ZnSe/ZnCdSe多量子阱的激子吸收谱及激子的非线性理论,归结其主要非线性机制为激子态的相空间填充和激子带展宽.  相似文献   

5.
在静压和液氮温度下观察到(CdSe)m/(ZnSe)n短周期超晶格中重空穴激子的复合发光和多达4阶的类ZnSeLO多声子喇曼散射,并观察到厚ZnSe势垒层的带边发光和限制在厚势垒层中的类ZnSeLO声子散射。结果表明,加压后(CdSe)m/(ZnSe)n短周期超晶格中的类ZnSe的1LO和2LO声子模频率分别以3.76和7.11cm^-1/GPa的速率向高频方向移动,超晶格阱层光致发光峰的压力系数  相似文献   

6.
在静压和液氮温度下观察到(CdSe)m/(ZnSe)n短周期超晶格中重空穴激子的复合发光和多达4阶的类ZnSeLO多声子喇曼散射,并观察到厚ZnSe势垒层的带边发光和限制在厚势垒层中的类ZnSeLO声子散射.结果表明,加压后(CdSe)m/(ZnSe)n短周期超晶格中的类ZnSe的1LO和2LO声子模频率分别以3.76和7.11cm-1/GPa的速率向高频方向移动,超晶格阱层光致发光峰的压力系数为59.8meV/GPa.与(CdSe)m/(ZnSe)n短周期超晶格共振时的类ZnSe1LO声子模频率比与ZnSe势垒层共振时的类ZnSe1LO声子模频率低2.0cm-1,反映了(CdSe)m/(ZnSe)n短周期超晶格中LO声子的限制效应  相似文献   

7.
我们首次利用Z-扫描技术在室温下研究了ZnCdSe-ZnSe/CaF2多量子了进中的三阶非线性,得到非线性系数n2为-4.46×10^-8esu。其主要非线性机理归结为ZnCdSe-ZnSe/CaF2多量子阱中的带填充效应。  相似文献   

8.
徐阿妹  朱海军 《半导体学报》1997,18(10):725-730
本利用RHEED、X射线双晶衍射及TEM等技术,研究了在Si(001)衬底上,用晶化了的列定形Ge层做缓冲层MBE生长Ge时,引入表面活化剂Sd所产生的影响。研究表明,Sd的引入将全使Si(001)衬底上无定形Ge膜的晶化温度显提高,并在一定的生长条件下,破坏Ge外延层的结晶性。  相似文献   

9.
采用进口分子束外延设备生长了GaAs/AlGaAs单量子阱和多量子阱材料。在理论分析和实验总结的基础上,对材料结构进行了优化,增加了GaAs/AlGaAs超晶格缓冲层来进行缺陷抑制,并在外延时精确地控制生长,这样获得的量子阱材料通过X射线双晶衍射和C-V测量表明:得到的材料性能良,为新型光电器件的制作和进一步的材料研究打下了基础。  相似文献   

10.
应变超薄层结构的组分、厚度、应变状态的直接检测,对于器件应用具有重要的意义,本文中,利用MOCVD方法得到高质量的InGaAs/GaAs量子阱材料,采用双晶衍射方法的弱信号收集技术,结合运动学理论模拟,得出同时包含几个不同阱宽的InGaAs/GaAs量子阶结构的重要参数,其检测结果与光致发光(PL)、透射电子显微镜(TEM)等方法的测试结果基本一致,表明X射线双晶衍射方法是检测超薄层应变量子阱结构的一个有效方法.  相似文献   

11.
Arrays of Ge quantum dots in unstrained GaAs/ZnSe/Ge heterostructures were obtained by molecular-beam epitaxy for the first time. Their spatial parameters are examined by scanning tunneling microscopy, and their electronic structure is studied by Raman spectroscopy.  相似文献   

12.
High-quality quaternary ZnSTeSe epitaxial layers with uniform carrier concentration of 1/spl times/10/sup 17/ cm/sup -3/ were successfully grown on p-GaAs substrates by molecular beam epitaxy. P-down ZnSTeSe/ZnSe/GaAs heterostructure photodiodes were also fabricated. It was found that the maximum quantum efficiency of the fabricated ZnSTeSe photodiodes was around 75% with a large spectral width of 500 nm.  相似文献   

13.
The continuous wave operation of an ZnSe/ZnMgSSe laser diode was achieved for the first time at 77 K. Blue stimulated emission was observed at a wavelength of 447 nm and the threshold current density was 225 A/cm/sup 2/.<>  相似文献   

14.
ZnSe/CdSe heterojunctions have been prepared by vacuum evaporation. By applying positive potential to the CdSe-layer and contacting the ZnSe by an electron beam current-voltage measurements have been made in the voltage range from about 5–50 V. The results can be described by ln j = a exp (bU12). High photosensitivity with a gain factor exceeding 100 has also been observed. The experiments suggest a theoretical model, which interpretes the current to be mainly caused by thermal emission of electrons from interface states.  相似文献   

15.
Atheoretical basis of optimally designed BRAQWET is presented.The optimum parameters of MgZnSSe/ZnSe BRAQWET are obtained by the calculation of band-structure according to the depletion approximation.  相似文献   

16.
ZnSe and ZnTe single-crystal layers have been grown onto (100) GaAs substrates by low-pressure metalorganic vapor-phase epitaxy (LP-MOVPE) using the triethylamine-dimethylzinc adduct [DMZn(NEt3)] as the zinc precursor. The selenium and tellurium precursors were H2Se (5% in H2) and di-isopropyltellurium (DiPTe), respectively. These two semiconductors have been grown with different VI/II molar ratios, at different growth temperatures, and with an overall growth pressure ranging from 40 to 400 Torr. Optimal growth parameters have been determined by optical means for the two materials. This information was then used to grow ZnTe/ZnSe strained-layer superlattices. We have studied structures grown on both ZnSe and ZnTe relaxed buffer layers which display a drastic dependence of the Stokes shift between photoluminescence and the optical bandgap on the nature of the buffer layer. Growth interruptions have been used to optimize the optical properties of the superlattices. Theoretical modeling of superlattice band structures has been performed using results of optical and structural characterizations. Observations of zone center transitions as well as excitons associated with the miniband dispersion of the superlattices are reported, in agreement with the theoretical calculation.  相似文献   

17.
采用基于LMTO-ASA的平均结合能计算方法,研究了在ZnSxSe1-x衬底上沿(001)方向外延生长的应变层异质结ZnS/ZnSe的价带带阶值。研究表明,应变的结果使价带带阶随衬底组分(x)的变化呈非线性且单调的关系;与其他理论计算和实验结果比较,本文的计算结果比较理想。  相似文献   

18.
19.
Li  X. Tao  I.W. Wang  W.I. 《Electronics letters》1995,31(6):491-493
A ZnSSe/ZnSe/CdZnSe light-emitting diode (LED) film grown on GaAs by molecular beam epitaxy (MBE) has been successfully transferred from a GaAs substrate to a silicon substrate by combining both mechanical polishing and chemical wet etching techniques. The external quantum efficiency of the LED was enhanced by more than a factor of 2 via insertion of a reflector layer beneath the device structure. The device can be implemented in hybrid quasimonolithic integration. Technology applications include fabrication of LEDs with enhanced external quantum efficiency and II-VI surface emitting lasers  相似文献   

20.
ZnO and ZnSe are proposed as n-type layers in ZnTe heterojunction diodes to overcome problems associated with the n-type doping of ZnTe. The structural properties and electrical characteristics of ZnO/ZnTe and ZnO/ZnSe/ZnTe heterojunctions grown by molecular beam epitaxy on (001) GaAs substrates are presented. ZnO shows a strong preference for c-plane (0001) orientation resulting in a nonepitaxial relationship and high density of rotational domains for growth on ZnTe (001). ZnSe/ZnTe structures demonstrate a (001) epitaxial relationship with high density of {111} stacking faults originating at the heterojunction interface. ZnO/ZnSe/ZnTe heterojunction diodes show excellent diode rectification and clear photovoltaic response with open-circuit voltage of V OC = 0.8 V.  相似文献   

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