气态源分子束外延InP和InAs基Ⅲ－Ⅴ族化合物材料

本文简要报告我们气态源分子束外延实验结果．材料是ＧａＡｓ（１００）衬底上外延的晶格匹配的Ｉｎｙ（Ｇａ１－ｘＡｌｘ）１－ｙＰ（ｘ＝０～１，ｙ＝０．５），ＩｎＧａＰ／ＩｎＡｌＰ多量子阱；在ＩｎＰ（１００）衬底上外延的ＩｎＰ，晶格匹配的ＩｎＧａＡｓ、ＩｎＡｌＡｓ以及ＩｎＰ／ＩｎＧａＡｓ、ＩｎＰ／ＩｎＡｓＰ多量子阱，ＩｎＧａＡｓ／ＩｎＡｌＡＳＨＥＭＴ等．外延实验是用国产第一台化学束外延（ＣＢＥ）系统做的．     

InP与In_（1－x）Ga_xAs_yP_（1－y）／InP的电解液电调制反射

研究了ＩｎＰ样品和Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ液相外延片在３００～８００ｎｍ范围内的电调制反射光谱。利用Ａｐｓｎｅｓ三点法计算了临界点能量、增宽因子和自旋轨道分裂值。通过实验曲线与理论公式的拟合，确定了临界点能维数及相位因子。并且间接提供了被测Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ四元合金的组份值及其它临界点能量值Ｅ０和Ｅ２。     

宽禁带Ⅱ－Ⅵ族四元合金Zn_（1－x）Mg_xS_ySe_（1－y）成分的定量俄

用分子束外延法在ＧａＡｓ（１００）衬底上生长了高质量的四元合金Ｚｎ（１－ｘ）ＭｇｘＳｙＳｅ（１－ｙ）薄膜．在对所生长的样品进行俄歇电子能谱、Ｘ射线衍射和喇曼散射研究后，提出了一种确定四元合金Ｚｎ（１－ｘ）ＭｇｘＳｙＳｅ（１－ｙ）组分的方法，即：利用ＺｎＳｙＳｅ（１－ｙ）和化学配比的ＭｇＳｅ作为标准样品，通过Ｘ射线衍射和喇曼散射测得标准样品ＺｎＳｙＳｅ（１－ｙ）中的Ｓ组分，再根据ＺｎＳｙＳｅ（１－ｙ）和ＭｇＳｅ的俄歇谱图，对各元素的相对灵敏度因子进行修正，然后利用相对灵敏度因子法比较精确地走出四元合金Ｚｎ（     

Ⅲ族锢源对LP－MOVPE方法生长In_（1－x）Ga_xAs材料的影响

本文报道了利用低压金属有机物汽相外延（ＬＰ－ＭＯＶＰＥ）技术，在（００１）ＩｎＰ衬底上生长Ｉｎ_（１－ｘ）Ｇａ_ｘＡｓ体材料及Ｉｎ_（１－ｘ）Ｇａ_ｘＡｓ／ＩｎＰ量子阶结构材料的结果．对于ＴＭＧ／ＴＥＩｎ源，Ｉｎ_（１－ｘ）Ｇａ_ｘＡｓ材料的非故意掺杂载流子依匿为７．２×１０１６ｃｍ－３，最窄光致发光峰值半宽为１８．９ｍｅＶ，转靶Ｘ光衍射仪对量子阶结构材料测到±２级卫星峰；而对于ＴＭＧ／ＴＭＩｎ源，非故意掺杂载流于浓度为３．１×１０￣１５ｃｍ￣（－３），最窄光致发光峰值半宽为８．９ｍｅＶ，转靶Ｘ光衍射仪对量子阶     

三元合金（GaSb）1—xGe2x,（InP）1—xGe2x的亚稳有序无序相变以及相变…

根据普适参数紧束缚方法得到的最近邻对原子相互作用能以及改进的Ｋｉｋｕｃｈｉ近似，我们计算了合金（ＧａＳｂ）１－ｘＧｅ２ｘ，（ＩｎＰ）１－ｘＧｅ２ｘ的亚稳相图，在计算亚稳相图时，Ｇｅ原子取为无序分布以消除相分离，对于亚稳合金（ＧａＳｂ）１－ｘＧｅ２ｘ，相应于亚稳有序无序相转变点的临界转变浓度Ｘ０为０．２６，对于亚稳合金（ＩｎＰ）１－ｘＧｅｘ，ｘ０为０．１６，计算机值及实验值符合较好，根据关联虚晶近似     

MBE生长的p－Hg_（1－x）Cd_xTe外延薄膜变磁场下的Hall系数及电导率

本文报道了利用分子束外延技术在ＧａＡｓ（２１１）Ｂ衬底上生长Ｈｇ１－ｘＣｄｘＴｅ／ＣｄＴｅ异质结，并通过ＶａｎｄｅｒＰａｕｗ（ＶｄＰ）方法测量Ｐ－Ｈｇ１－ｘＣｄｘＴｅ外延薄膜在不同温度及磁场下Ｈａｌｌ系数和电导率，采用最小二乘法对实验数据下行拟合，得到了混合导电机制下电子、重空穴和轻空穴的迁移率及载流子浓度．     

Zn1—xMgxSe外延半导体合金薄膜的红外反射光谱研究

用分子束外延方法在ＧａＡｓ（１００）衬底上生长了Ｚｎ１－ｘＭｇｘＳｅ（０≤ｘ≤１）三元半导体合金薄膜．在室温下测量了这些样品的红外反射光谱．采用介电函数的经典色散理论，并且考虑衬底的影响后，计算了样品的红外反射光谱并与测量结果作了比较．我们发现对于ｘ＜０．２，０．２＜ｘ＜０．５和ｘ≥０．５三种不同情形，反射光谱表现出不同的结构．     

三元合金 （GaSb）_（1－x）Ge_（2x），（IuP）_（1－x）Ge_（2x） 的亚稳有序无序相变以及相变对于能隙的影响

根据普适参数紧束缚方法得到的最近邻对原子相互作用能以及改进的Ｋｉｋｕｃｈｉ近似，我们计算了合金（Ｇａｓｈ）１－ｘＧｅ２ｘ，（ＩｎＰ）１－ｘＧｅ２ｘ的亚稳相图．在计算亚稳相图时，Ｇｅ原子取为无序分布以消除相分离．对于亚稳合金（Ｇａｓｈ）１－ｘＧｅ２ｘ，相应于亚稳有序无序相转变点的临界转变浓度ｘｃ为０．２６，对于亚稳合金（ＩｎＰ）１－ｘＧｅ２ｘ，ｘｃ为０．６１．计算值与实验值符合较好．根据关联虚晶格近似我们还计算了合金的能隙．     

生长在Si（001）衬底上的Ge_xSi_（1－x）合金的电子能带结构

采用紧束缚方法对生长在Ｓｉ（００１）衬底上的ＧｅｘＳｉ１－ｘ合金形变层的电子能带结构进行了计算，并与ＧｅｘＳｉ１－ｘ合金的能带结构进行了比较．计算结果表明，对大部分合金组分ｘ（０≤ｘ≤０．９），形变层的导带底处在△轴上；当ｘ≥０．９后，导带底处在Ｌ点．形变层的直接能隙Ｅｇ（）及间接能隙Ｅｇ（△）和Ｅｇ（Ｌ）都比同组分ｘ的合金小，其下降量随组分ｘ的增大而增大．形变层的价带顶自旋－轨道分裂值△ｓ。也比相同组分的合金大，其增大值也随合金组分的增加而增加．     

InGaAsP及其量子阱结构的LP－MOCVD

报道了用低压金属有机化学汽相淀积（ＬＰ－ＭＯＣＶＤ）技术在（１００）ＩｎＰ衬底上生长ＩｎＧａＡｓＰ体材料及ＩｎＧａＡｓＰ（１．３μｍ）／ＩｎＧａＡｓＰ（１．６μｍ）量子阱结构的生长条件和实验结果。比较了５５０℃和５８０℃两个生长温度下Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ体材料及相应量子阱结构的特性，表明在５８０℃生长条件下，晶体具有更好的质量和特性。     

Current controlled liquid phase epitaxial (CCLPE) growth of InGaAs on (100) InP

High quality epitaxial layers of In_xGa_1−xAs (x = 0.53) were grown on semi-insulating (Fe-doped) (100) InP sub-strates. The layers were grown at a constant furnace temperature of 640°C by passing a direct electric current (0–10A/cm²) from the substrate to the melt. In order to minimize the out-diffusion of Fe atoms from the bulk of the substrate during the melt saturation, the substrate was kept at a cold temperature region (340°C) within the growth chamber and remotely loaded in the graphite boat just prior to the initiation of the growth cycle. In addition to pre-venting the out-diffusion of Fe atoms, this procedure sub-stantially reduced the thermal degradation of the InP sub-strate surface. The above technique produced high quality layers having uniform thickness and good surface morphology. A study of the dependence of growth rate on the applied current density yielded an average growth rate of 0.06μm/ A-min. Room temperature Hall measurements on layers grown by CCLPE resulted in Hall mobilities μ₃₀₀ = 8900cm²/V-sec at a carrier concentration of 6.2 × l0¹⁶cm⁻³. The improve-ment in the mobility achieved by the CCLPE technique is attributed to a reduced out-diffusion of scattering centers from the substrate into the growth layer, as well as to the higher quality of epitaxial layers normally achieved by CCLPE.     

AFM observation of OMVPE grown ErP on InP (0 0 1), (1 1 1)A and (1 1 1)B substrates

ErP has been grown on InP (0 0 1), (1 1 1)A and (1 1 1)B substrates by low-pressure organometallic vapor-phase epitaxy. The morphological change with growth temperature has been explored by atomic force microscope. On all the substrates, ErP is grown in island structure. Height and area size of the ErP islands on (1 1 1)A substrate exhibit an obvious dependence on growth temperature. ErP islands grown at 540°C, that is the suitable temperature for ErP formation, gather to step edges to make wires.     

Variation of the thickness and composition of lpe InGaAsP,InGaAs, and InP layers grown from a finite melt by the step-cooling technique

Constant composition InGaAsP and InGaAs epitaxial layers can be grown using the step-cooling technique. However, the requirement of a fixed growth temperature limits the maximum thickness that can be obtained. The thickness of InGaAsP (λ_g = 1.15 μm@#@), InGaAs (λ_g = 1.68 μm), and InP liquid phase epitaxial layers grown on (100) InP sub-strates by the step-cooling technique has been measured as a function of growth time. (λ_g is defined as the wave-length corresponding to the band gap of the epitaxial layer). For long growth times, the effect of the finite growth solution becomes important, and beyond a distinct growth time, constant composition growth can no longer be maintained. The maximum constant composition layer thick-ness obtainable is not severely restricted by the fixed growth temperature, and from the experimental results this maximum thickness can be estimated for any melt size.     

在蓝宝石衬底上低压MOVPE生长GaN单晶

研究用水平反应室低压金属有机物汽相外延方法在Ｃ面及Ｒ面蓝宝石衬上外延生长ＣａＮ单晶。讨论了反应室中气流分布和汽相反应对ＧａＮ外延生长的影响提出了不同的衬底晶向对外延ＧａＮ表面形貌产生影响的机制。     

Atomic layer epitaxy of InP

In this work we will discuss the growth conditions for ALE of InP. Growth experiments were carried out in a LP-MOCVD system with a fast switch gas manifold. InP layers were deposited by pulsing TMIn and PH₃, using Argon as carrier gas. A self limiting growth rate at 1 ML/cycle has been obtained with a substrate temperature as low as 320-360° C. InP epitaxial layers were grown on GaAs and InP substrates, and on GaInAs(P) layers previously deposited by conventional MOCVD. Selective area epitaxy on InP using a Si₃N₄ mask was also demonstrated. Results of this study are very encouraging for hybrid MOCVD/ALE growth of In-based compounds.     

X-ray Diffraction Imaging of Improved Bulk-Grown CdZnTe(211) and Its Comparison with Epitaxially Grown CdTe Buffer Layers on Si and Ge Substrates

Large-area high-quality Hg_1–x Cd _x Te sensing layers for infrared imaging in the 8 μm to 12 μm spectral region are typically grown on bulk Cd_1–x Zn _x Te substrates. Alternatively, epitaxial CdTe grown on Si or Ge has been used as a buffer layer for high-quality epitaxial HgCdTe growth. In this paper, x-ray topographs and rocking-curve full-width at half-maximum (FWHM) data will be presented for recent high-quality bulk CdZnTe grown by the vertical gradient freeze (VGF) method, previous bulk CdZnTe grown by the vertical Bridgman technique, epitaxial CdTe buffer layers on Si and Ge, and a HgCdTe layer epitaxially grown on bulk VGF CdZnTe.     

The influence of a hydride preflow on the crystalline quality of InP grown on exactly oriented (100)Si

Several microns thick epitaxial InP films have been successfully deposited on exactly oriented (100) Si substrates by metal-organic vapour-phase epitaxy. We have studied the influence of a hydride preflow before buffer growth on the crystalline quality of the InP by measuring the surface roughness, by X-ray diffractometry, TEM and SEM investigations, and by detection of anti-phase-domains. Generally, an AsH₃ preflow instead of PH₃ improved the crystalline perfection considerably. Furthermore, if AsH₃ is introduced only during cool-down between 700 and 900° C after the thermal cleaning step anti-phase-domain free InP is grown.     

Metalorganic vapor phase epitaxial growth and structural characterization of GaAs/InP heterostructures

Highly mismatched GaAs epitaxial layers with thickness ranging from 15 nm to 7 μm have been grown on InP substrates by atomospheric pressure metalorganic vapor phase epitaxy. Layers thinner than 30 nm exhibited 3-D growth mechanism; in the thicker layers, the islands coalesced and then the growth followed the layer by layer mechanism. The elastic strain and the extended defects have been studied by high resolution x-ray diffraction and transmission electron microscopy, respectively. The common observation of planar defects, misfit, and threading dislocations in the layers has been confirmed. The results on the elastic strain release have been discussed on the basis of the equilibrium theory.     

Epitaxy of FeAl films on GaAs(100) by molecular beam epitaxy

Intermetallics that coexist with III-V’s in the bulk are expected to form thermodynamically stable overlayers when deposited as a thin film. To the extent that adsorption kinetics do not play a role, these films should be abrupt and able to withstand high temperature processing. Some of these films have been found to be epitaxial after heating in vacuum. FeAl has been found to form pseudomorphic films on InP(l00) substrates and to grow in a layer-by-layer mode even when code-posited. To explore the role of stoichiometry and crystal strain, we have used reflection high energy electron diffraction (RHEED) to compare the growth of Fe _x -Al_1−x on GaAs(l00) to its growth on InP substrates. In both cases RHEED intensity oscillations are observed at 200° C, indicating two-dimensional island formation and layer-by-layer growth. For both, the growth is pseudomorphic on an AlAs buffer layer, with any lattice constant change less than 0.3%. When the intermetallics were codeposited, the growth proceeded via double layer formation forx < 0.7 and via single layers for largex. The films were stable to 550° C. Subsequent growth of AlAs was three dimensional.     

Initial stages of InP/GaP (100) and (111)A,B grown by metal organic chemical vapor deposition

The initial stages of the three-dimensional metal organic vapor phase epitaxy growth of InP/GaP (100) and (111)_A,B were studied by atomic force microscopy (AFM) and Rutherford back scattering (RBS). We have shown that the heteroepitaxial growth takes place under Stranski–Krastanov mode (layer by layer and dislocation free island growth). By combining RBS and AFM results, we show that the wetting layer is about 0.51 and 0.4 nm for (100) and (111)_A,B orientated substrates, respectively. The critical thickness is found to depend on the substrate orientation. However, we show by the AFM technique that the shape, the height and the size of uncapped InP/GaP self-organized nanostructures depend on the amount of InP deposited and on the substrate orientation. In particular, the structure grown on (111)_A,B substrate presents higher islands than the structure grown on (100). Therefore, the formation of nanostructures on substrates different from (100) is an interesting possibility to be investigated.