分子束外延生长Al掺杂n型ZnS_(1-x)Tex的类DX中心

应用光致发光 (PL )、电容 -电压 (C- V)、深能级瞬态谱 (DL TS)和光电导 (PC)技术系统研究 Al掺杂 Zn S1 - xTex 中与 Al有关的类 DX中心 .实验结果表明 ,Zn S1 - x Tex 中存在与 - 族半导体 DX中心相类似的性质 .获得与 Al有关的类 DX中心光离化能 Ei (～ 1.0 e V和 2 .0 e V)和发射势垒 Ee (0 .2 1e V和 0 .39e V) ,这表明 Zn S1 - x Tex大晶格弛豫的出现是由类 DX中心引起     

分子束外延生长A1掺杂n型ZnS1—xTex的类DX中心

应用光致发光（PL）电容--电压（C-V）、深能级瞬态谱（DLTS）和光电导（PC）技术系统研究A1掺杂ZnS1-xTex中与A1有关的类DX中心,实验结果表明,ZnS1-xTex中存在与Ⅱ-Ⅴ族半导体DX中心相类似的性质。获得与A1有关的类DX中心光离化能Ei(～1.0eV和2.0eV）和发射势垒Ee(0.21eV和0.39eV）,这表明ZnS1-xTex大晶格弛豫的出现是由类DX中心引起。     

ZnCl2掺杂n型ZnSe的分子束外延生长

利用分子束外延(MBE)技术,以5N的ZnCl2作为掺杂源,在半绝缘GaAs (001)衬底上异质外延生长ZnSe:Cl单晶薄膜.研究发现,掺入ZnCl2后,ZnSe外延层的结晶质量和表面形貌与本征ZnSe外延层相比变差,双晶X射线摇摆曲线(DCXRC)的ZnSe (004)衍射峰半峰宽(FWHM)从432 arcsec增大到529 arcsec,表面均方根粗糙度(RMS)从3.00 nm增大到3.70nm.当ZnCl2掺杂源炉的温度为170℃时,ZnSe样品的载流子浓度达到1.238×1019 cm-3,可以满足结型器件制作和隧道结材料设计的要求.     

Ⅱ—Ⅵ族宽带隙半导体的分子束外延

我们用分子束外延法已生长出了ZnSe、ZnTe单晶薄层。外延层的生长速率基本上由分子束流量和衬底温度决定。本文讨论了这种二元化合物的生长速率,包括衬底温度、结晶性及分子束强度,并和实验结果作了比较分析。所获得的生长速率与衬底温度和入射束比的关系能用原子表面覆盖度的动力学方程得到解释。     

分子束外延δ掺杂研究

用分子束外延生长了δ掺杂结构,并用电化学C-V和汞探针C-V测量了载流子的分布特性,其半峰宽约85(?)。δ掺杂用于AlGaAs/GaAs调制掺杂异质结,在77K具有较好的输运特性。     

双腔室分子束外延复合体在Ⅲ-Ⅴ族和Ⅱ-Ⅵ族半导体异质结生长中的应用(英文)

半导体光电子学是当前科技发展最快的一个领域,光电子器件的增长需要加强新材料技术的研究与开发,Ⅲ -Ⅴ族和Ⅱ-Ⅳ族纳米结构生长的双腔室分子束外延复合体是目前工艺设备一个最好的例子,可以解决长期以来纳米光子学和纳米电子学的问题。     

利用分子束外延生长高质量应变平衡InAs/InAsSbⅡ类超晶格

利用分子束外延技术在GaSb衬底上生长了高质量的InAs/InAsSb（无Ga）Ⅱ类超晶格。超晶格的结构由100个周期组成,每个周期分别是3.8 nm厚的InAs层和1.4 nm厚的InAs_0.66Sb_0.34层。在实验过程中出现了一种特殊的尖峰状缺陷。利用高分辨率x射线衍射（HRXRD）、原子力显微镜（AFM）和傅里叶变换红外光谱（FTIR）对外延的超晶格进行了表征和分析。结果表明,优化后的样品几乎为零晶格失配,超晶格0级峰半峰宽为39.3 arcsec,表面均方根粗糙度在10 μm×10 μm范围内达到1.72 ?。红外吸收光谱显示50%的截止波长为4.28 μm,PL谱显示InAs/InAs_0.66Sb_0.34超晶格4.58 μm处有清晰锐利的发光峰。这些结果表明,外延生长的InAs/InAsSb超晶格稳定性和重复性良好,值得进一步的研究。     

ZnO Grown on (111) ZnS Substrates by Plasma-Assisted Molecular Beam Epitaxy

ZnO thin films have been grown by plasma-assisted molecular beam epitaxy on (111) ZnS substrates. The films grown on Zn-face substrates showed better structural and optical properties compared with those grown on S-face substrates, as demonstrated by x-ray diffraction and photoluminescence measurements. Scanning electron microscopy measurements indicated that ZnO films grown on Zn-face substrates also have smoother surface morphology. It is also found that higher growth temperature yields films with better quality.     

Study of HgCdSe Material Grown by Molecular Beam Epitaxy

Much progress has been made in developing high-quality HgCdTe/Si for large-area focal-plane array (FPA) applications. However, even with all the material advances made to date, there is no guarantee that this technology will be mature enough to meet the stringent FPA specifications required for long-wavelength infrared (LWIR) systems. With this in mind, the Army Research Laboratory (ARL) has begun investigating HgCdSe material for infrared (IR) applications. Analogous to HgCdTe, HgCdSe is a tunable semiconductor that can detect any wavelength of IR radiation through control of the alloy composition. In addition, several mature, large-area bulk III–V substrates are nearly lattice matched to HgCdSe, giving this system a possible advantage over HgCdTe, for which no scalable, bulk substrate technology exists. We have initiated a study of the growth of HgCdSe using molecular beam epitaxy (MBE). Growth temperature and material flux ratios were varied to ascertain the best growth conditions. Smooth surface morphology has been achieved using a growth temperature much lower than that used for HgCdTe. Additionally, zero void defects were nucleated at these lower temperatures. Preliminary data suggest a linear relationship between the Se/Cd flux ratio used during growth and the cutoff wavelength as measured by Fourier-transform infrared (FTIR) spectroscopy.     

Defects in HgTe and CdHgTe Grown by Molecular Beam Epitaxy

The defect morphology in HgTe and CdHgTe was studied in (211)B-oriented layers grown in a 20°C temperature range around the optimal growth temperature. The density of defects varies strongly with the growth temperature. In HgTe, the shape of the microvoid defects is very sensitive to the growth temperature and can be used to determine the deviation from the optimal growth temperature. Using thermodynamical modeling, the optimal growth temperature for CdHgTe can then be calculated. We describe a mechanism for the formation of microvoids and needles which involves preferential surface diffusion of Te combined with an impurity or defect on the substrate. Microvoids on (111)B-oriented partially twinned HgTe layers were also studied. The microvoids in the twinned parts of the layer were found to be rotated 180 deg relative to the untwinned parts of the layer.     

AlInP–AlGaInP Quantum-Well Lasers Grown by Molecular Beam Epitaxy

We have examined a possibility to use an Al $_{x}$In $_{1 - {x}}$P layer as an active region of a 650-nm semiconductor laser. Encouraging results have been obtained with compressively strained oxide-stripe AlInP–AlGaInP quantum-well lasers, which operated in continuous-wave mode at room temperature, producing an optical power of 460 and 320 mW per uncoated facet at 10 $^{circ}$C and 20 $^{circ}$C, respectively. In pulsed mode, a power level of 780 mW/facet was achieved at 2-A drive current at 5 $^{circ}$C. The results indicate that wide-bandgap AlInP affords an opportunity to develop lasers for the wavelengths $600leq lambda leq 650$ nm, which is difficult to achieve by any semiconductor heterostructure.      

Optical Properties of MQW Optical Waveguides in Electroabsorption MQW Modulator

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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.     

重碳掺杂p型GaAsSb的GSMBE生长及其特性

以四溴化碳(CBr4)作为碳掺杂源,采用气态源分子束外延(GSMBE)技术生长了InP衬底上晶格匹配的重碳掺杂p型GaAsSb材料.通过改变CBr4压力,研究了掺杂浓度在(1～20)×1019cm-3范围内的掺杂特性,得到的最大掺杂浓度为2.025×1020cm-3,相应的空穴迁移率为20.4cm2/(V·s).研究了不同生长温度对掺碳GaAsSb外延层组分、晶格质量和表面粗糙度的影响,结果表明480℃是生长优良晶格质量的最优温度.