分子束外延ZnSe/ZnS_xSe_(1-x)超晶格光学特性

用分子束外延方法在 Ga As(10 0 )衬底上生长了高质量的 Zn Se/ Zn Sx Se1 - x(x=0 .12 )超晶格结构 ,通过 X射线衍射谱和光致发光谱 ,对其结构特性和光学特性进行了研究 .结果表明 :在 4 .4 K温度下 ,超晶格样品显示较强的蓝光发射 ,主发光峰对应于阱层 Zn Se的基态电子到重空穴基态的自由激子跃迁 ,而且其峰位相对于 Zn Se薄膜的自由激子峰有明显蓝移 .从理论上分析计算了由应变和量子限制效应引起的自由激子峰位移动 ,理论和实验结果相吻合     

分子束外延ZnSe/ZnSxSe1-x超晶格光学特性

用分子束外延方法在GaAs(100)衬底上生长了高质量的ZnSe/ZnSxSe1-x(x=0.12)超晶格结构，通过X射线衍射谱和光致发光谱，对其结构特性和光学特性进行了研究。结果表明：在4．4K温度下，超晶格样品显示较强的蓝光发射，主发光峰对应于阱层ZnSe的基态电子到重空穴基态的自由激子跃迁，而且其峰位相对于ZnSe薄膜的自由激子峰有明显蓝移。从理论上分析计算了由变就和量子限制效应引起的自由激妇峰位移动，理论和实验结果相吻合。     

分子束外延生长Al_xGa_(1-x)As/GaAs超晶格及结构、光学特性研究

报道了分子束外延生长80个周期的Al_xGa_(1-x)As/GaAs超晶格,X射线衍射和透射电镜的结果表明超晶格样品有良好的结构特性,光反射光谱观察到阱内的电子跃迁过程,其结果与理论计算相符。     

ZnSe_(1-x)S_x-ZnSe应变超晶格结构光致发光研究

本文研究了ZnSe_(1-x)S_x-ZnSe应变超晶格结构在77K时自由激子的光致发光的线型随激发光密度、势阱涨落、势垒高度的涨落及各层厚对超晶格发光峰E_(?)的影响,并利用Kronig-Penney模型计算了n=1的激子峰值能量与势阱宽度、势垒高度涨落的关系.首次从实验上分析了77-250K温度范围内ZnSe_(1-x)S_x-ZnSe应变超晶格激子发光的线型与各参量的密切关系.     

分子束外延生长p型ZnSe-ZnTe超晶格

一种p型应变层超晶格已用调制掺杂技术实现,这种超晶格材料是由不掺杂的ZnSe层和掺Sb的ZnTe层交替生长组成的,电学性质已由霍尔效应测量获得。p型应变层超晶格的空穴迁移率为220—250cm~2/V·s,空穴浓度为3—5×10~(14)/cm~3。     

Zn1—xMnxSe／ZnSe应变超晶格的分子束外延生长及特性研究

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     

超晶格结构的X射线衍射拟合计算

运用X射线衍射运动学理论研究了[(Ga_(1-x)Al_xAs)_m(GaAs)_n ]_N/GaAs(001)-维超晶格的结构,通过模拟计算,精确确定了超晶格的结构参数.本方法可用于各种超晶格结构,具有普遍意义.另外,还对超晶格卫星峰强度的非称性和超晶格中叠层界面处存在过渡层的影响进行了讨论.     

Characterization of GaNxAs1-x Alloy Grown on GaAs by Molecular Beam Epitaxy

Ga Nx As1 - x,the combination of small amount of nitrogen and Ga As,has beenexperimentally observed with the band gaps several hundreds me V lower than that ofGa As[1～ 4] .The alloy has attracted considerable attention in the applicat...     

Characterization of GaNxAs1-x Alloy Grown on GaAs by Molecular Beam Epitaxy

The GaNxAs1-x alloy has been investigated which is grown on GaAs (100) substrate by molecular beam epitaxy with a DC-plasma nitrogen source. The samples are characterized by high resolution X-ray diffraction (HRXRD) and low temperature photoluminescence (PL) measurements. Both HRXRD and PL measurements demonstrate that the crystalline and optical qualities of GaNxAs1-x alloy degrade rapidly with the increase of N composition. The nitrogen composition of 4.5 % can be obtained in GaNxAs1-x/GaAs quantum well by optimizing growth conditions,through which a photoluminescence peak of 1201nm is observed at a low temperature (10 K). The dependence of GaNxAs1-x band gap energy on the nitrogen composition in this investigation corresponds very well with that of the theoretical one based on the dielectric model when considering the effect of the strain. At the same time,we also demonstrate that the bowing parameter of GaNxAs1-x alloy is composition dependent.     

N-型ZnSe:Cl的分子束外延生长

本文报道利用分子束外延(MBE)技术,采用高纯ZnCl_2作掺杂源,成功地进行了n—型ZnSe:Cl的分子束外延生长。n-ZnSe:Cl/p-GaAs异质结构的伏-安(I—V)特性和热探针测试显示外延层呈n型导电特性。反射高能电子衍射(RHEED)和x射线衍散谱测量表明ZnSe:Cl外延层具有较好的晶体质量。     

分子束外延生长的Ge_xSi_(1-x)/Si应变超晶格的X射线衍射研究(英文)

The structural properties of GexSi1-x/Si strained-layer superlattices grown by molecular beam epitaxy are investigated using conventional X-ray θ-2θ scans with a scintillation counter. The experimental diffraction curves for the small-angle reflection and symmetric Bragg reflection are analyzed by applying the optical mutilayer theory and a approach of the dynamical theory of X-ray diffraction for distorted crystals. The structure parameters of superlattices can be obtained without Fourier transformation or computer fitting. The theoretical fit of the experimental diffraction curves yields detailed information on the strain profile,the chemical composition, and the thickness of individual layers of superlattices, which provides a powerful tool to evaluate the structural perfection of GexSi1-x/Si strained-layer superlattices.     

Effects of Growth Conditions on Optical Properties ofGa In NAs/Ga As Quantum Well Grown by Molecular Beam Epitaxy

During the process of molecular beam epitaxy employing a DC plasma as N source, the effects of the growth temperature, growth rate and As 4 pressure on the optical properties of GaInNAs Quantum Well(QW) are similar to those of InGaAs QW with the same In contents. In the range of 400 to 470℃, elevating growth temperature is beneficial to the improvement in the photoluminescence (PL) peak intensity of GaInNAs QW, but obviously broadens the full width at half maximum PL peak. The improvement of optical properties and the reduction of N incorporation have been observed by increasing the growth rate. As 4 pressure mainly affects the optical properties of GaInNAs QW rather than N incorporation does.     

Effects of Growth Conditions on Optical Properties of GaInNAs/GaAs Quantum Well Grown by Molecular Beam Epitaxy

Long wavelength ( 1.3 or 1.55μm) laser diodes have attracted much attention in re-centyears due to the minimum loss in the optical fiber communication. These wavelengthsare accessible to InGaAsP/InP based on semiconductor activ...     

Effects of Growth Conditions on Optical Properties of GaInNAs/GaAs Quantum Well Grown by Molecular Beam Epitaxy

During the process of molecular beam epitaxy employing a DC plasma as N source,the effects of the growth temperature, growth rate and As4 pressure on the optical properties of GaInNAs Quantum Well(QW) are similar to those of InGaAs QW with the same In contents.In the range of 400 to 470℃, elevating growth temperature is beneficial to the improvement in the photoluminescence (PL) peak intensity of GaInNAs QW, but obviously broadens the fullwidth at half maximum PL peak. The improvement of optical properties and the reduction of N incorporation have been observed by increasing the growth rate. As4 pressure mainly affects the optical properties of GaInNAs QW rather than N incorporation does.