MOVPE法生长HgCdTe/CdZnTe结构薄膜研究

碲锌镉(CdZnTe)衬底是生长红外焦平面列阵(IRFPAs)所用碲镉汞(HgCdTe)薄膜材料的首选衬底.本文讨论在单晶的碲锌镉衬底上,用MOVPE法生长一层碲锌镉过渡层,可以避免单晶碲锌镉衬底的一些杂质和缺陷延伸到碲镉汞薄膜材料中而影响到碲镉汞薄膜的结构质量.实验表明,有碲锌镉过渡层的碲镉汞薄膜的结构质量有了较大改善.     

超薄膜Si外延生长过程的动力学蒙特卡罗模拟

建立超薄膜Si外延生长的晶格一动力学蒙特卡罗模型,并应用该模型模拟了Si原子在Si（111）基底上外延生长的过程．系统研究了沉积时间、基片温度对于薄膜初始生长形貌的影响,如影响粒子的扩散与凝聚、岛的生长等微观过程．     

Zn_(0.85)Co_(0.14)Cu_(0.01)O薄膜的制备及其微结构

用电子束蒸镀方法在250℃~450℃的衬底温度范围内在单晶Si衬底(111)晶面上成功生长了Zn0.85Co0.14Cu0.01O薄膜,并研究了衬底温度对薄膜质量的影响,结果表明:当衬底温度为400℃时,外延膜取向性最好,且其(002)衍射峰半高宽最窄,仅为0.408°。     

ZnO.85 Co0.14 Cu0.01O薄膜的制备及其微结构

用电子束蒸镀方法在250℃～450℃的衬底温度范围内在单晶Si村底(111)晶面上成功生长了Zn0.85 Co0.14 Cu0.01O薄膜,并研究了衬底温度对薄膜质量的影响,结果表明:当衬底温度为400℃时,外延膜取向性最好,且其(002)衍射峰半高宽最窄,仅为0.408°.     

稀磁半导体GaMnAs的物理性质研究

利用低温分子束外延技术制备高质量的GaMnAs薄膜,通过XRD对样品进行分析,从实验和理论上分析生长条件、退火条件对薄膜缺陷及薄膜性能的影响.尤其是分析系统的研究间隙位Mn原子与As反位原子缺陷的变化,从而深入理解掺杂原子的周围结构与磁性之间的关系,为下一步制备自旋器件提供高载流子浓度、高居里温度的（Ga,Mn）As材料提供了可能性.     

Al和N极性AlN生长特性的第一性原理

使用第一性原理计算方法对Al和N极性AlN表面和生长特性的差异开展了研究.构建未吸附和吸附一个原子或原子层的Al和N极性AlN表面结构进行模拟和理论计算.结果表明：Al极性AlN比N极性AlN更稳定,并且在生长时将具有更高的生长速率;在富N的生长环境下,N极性AlN的生长容易在表面形成双N原子层而出现反型畴;Al和N原子在Al极性表面上更容易扩散,所以外延生长的Al极性面AlN将会具有更加平整的表面形貌.     

AlSb（110）基外延生长Bi薄膜的第一性原理研究

用基于密度泛函理论的第一性原理方法研究了在A lS b （110）衬底表面外延生长1～6层Bi薄膜的能带结构,计算了它们的带隙。研究发现,不同厚度的Bi薄膜显示出传导性质的奇偶振荡,1层和3层显示出非金属性质,2层和4层及更高的层数转变为金属性质。     

低温锗量子点缓冲层技术生长硅锗弛豫衬底研究

为了提高生长在硅衬底上的硅锗弛豫衬底的质量,提出了低温锗量子点缓冲层技术,分析了该技术在应变弛豫的促进,表面形貌的改善,位错密度的降低等方面的作用机理。基于低温锗量子点缓冲层技术,利用超高真空化学气相淀积系统,在硅衬底上生长出高质量的硅锗弛豫衬底。锗组份为0.28,厚度不足380 nm的硅锗弛豫衬底,应变弛豫度达到99%,表面没有Cross-hatch形貌,表面粗糙度小于2 nm,位错密度低于105 cm-2。     

Si基上Co、Ta、NiO生长次序对界面结构的影响

用磁控溅射方法在Si衬底上制备了一系列NiO、Ta、Co的薄膜与多层膜,利用掠入射X射线散射方法研究了不同生长顺序的薄膜的表面、界面结构与形态,结果表明各层的沉积次序会影响各层的形态,尤其是SiO2层的厚度、质量密度等,对各层之间的界面粗糙度也会产生很大影响。进而研究了自旋阀结构的多层膜的界面形态和粗糙度,这对于解释含NiO的Co/Cu/Co基自旋阀的磁电阻提升提供了结构依据。     

Fe／Mo（110）的电磁性质：第一性原理研究

应用自旋极化的第一性原理对在Mo（110）衬底上生长Fe薄膜进行系统研究．计算结果表明：紧邻界面的Mo原子层向外驰豫,而Fe原子层则表现向内驰豫．Fe／Mo（110）系统的键合表现为各向异性,在平行于Mo（110）表面方向,各个原子之间都表现为金属键,而在垂至于Mo（110）表面方向,Fe原子之间、Fe原子和Mo原子之间却表现为金属键．Fe／Mo薄膜中,Fe原子的磁矩大于体材料Fe原子的磁矩,以铁磁方式排列,并且在紧邻界面的Mo原子诱导出少量的磁矩,这些磁矩与Fe原子以反铁磁的方式排列．     

An ultrahigh vacuum chemical vapor deposition system and Si, GeSi epitaxy on a three-inch Si wafer

An ultrahigh vacuum chemical vapor deposition (UHV/CVD) system with reflection high energy electron diffraction (RHEED) was introduced. The Si epilayers and SiGe strained-layers on three-inch Si (100) substrates were grown in this UHV/CVD system. The substrate temperature during growth was from 550°C to 780°C. The properties of epilayers were characterized by high-resolution cross-sectional transmission electron microscopy (TEM), double crystal X-ray diffraction (DCXRD), and spreading resistance (SPR). A B-doped SiGe epilayer with uniform resistivity distribution was grown. Project supported by NSFC and Science Commission Program of Zhejiang Province of China.     

企业的内涵增长率和可持续增长率

介绍了内涵增长率和可持续增长率的含义，通过实例数据对比验证了在内涵增长率、可持续增长率和某种实际增长率情况下销售增长对企业资本结构和长期发展的影响。得出结论企业必须选择适当的发展速度，可持续增长率是企业发展速度的参照。     

MgO引发剂对铝合金原位氧化生长的影响

通过热重分析实验,研究了在高温空气气氛中覆盖在Al-Zn—Si合金表面的MgO引发剂对铝合金直接氧化生长过程的作用。结果表明：MgO能显著缩短Al-Zn—Si合金熔体直接氧化所需的孕育期及Al2O3／Al复合材料的生长时间。同时发现MgO有助于Al2O3／Al复合材料以光滑的方式进行氧化生长,形成细化胞状晶团,提高组织结构的均匀度和材料的致密度。促进Al2O3／Al复合材料生长的MgO覆盖最佳量为12mg／cm^2。     

多孔超弹性矩形板中微孔的增长

The analyses of finite deformation and stress for a hyperelastic rectangular plate with some voids under an uniaxial extension were conducted. The governing differential equations were given from the incompressibility condition of the material. The solution was approximately obtained from the minimum potential energy principle. The growth of voids was discussed. One can see that an initial central circular-cylinder void becomes an elliptic-cylinder void, but an initial non-centeral circular-cylinder void becomes an elliptic-like cylinder void and the center of void has a shift. The stress distributions along the edges of voids were given and the phenomenon of stress concentration was observed. The influences of the distribution manner and size of voids, as well as the distance between them on the growth of voids were analyzed.     

Polycrystalline ZnSxSe1-x thin films deposited on ITO glass by MBE

MBE growth of ZnSxSe1-x thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these films indicated that the as-grown polycrystalline ZnSxSe1-x thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290℃. Both AFM and TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnSxSe1-x thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional micrograph showing a well defined columnar structure.     

Optical transition and carrier relaxation in self-assembled InAs/GaAs quantum dots with InAlAs and InGaAs combination cap layer by resonant excitation

The photoluminescence （PL） spectra of self-assembled InAs/GaAs quantum dots （QDs） with InAlAs/InGaAs combination cap layer grown by molecular beam epitaxy are studied under different excitation conditions.The intrinsic optical properties of InAs QDs are investigated under resonant excitation condition.A longitudinal optical （LO） phononassisted peak can be well resolved under Eex 〈 E GaAs g,which give evidence that the phonon-related process is dominated for carrier relaxation in InAs QDs with InAlAs/InGaAs combination cap layer when they are under resonant excitation condition.A rate equation model is established to interpret the difference of thermal activation energy （Ea）.The Ea measured under Eex 〈 E GaAs g,can exactly describe the intrinsic physical mechanism of temperature-induced quenching in InAs QDs,because it can be irrespective of the barrier materials.This result will benefit to validating the parameters of quantum dots infrared photodetector （QDIP） in sequent procedure of device fabrication.     

不同光照强度对薇甘菊幼苗生长和形态的影响

比较了生长在不同光照强度下的薇甘菊 (Mikainamicrantha) 幼苗的生长型。结果表明 :苗高、节间长、比叶面积、叶面积比、总叶面积、净同化速率、支持结构生物量比、根生物量比和根冠比随着光照强度的变化而改变 ;然而 ,比茎长、比叶柄长、总生物量、相对生长速率和叶片生物量比却保持相对的稳定。说明薇甘菊幼苗对不同的光强梯度具有不同的可塑性和适应性。     

Higher Education in India: Growth, Concerns and Change Agenda

Higher education in India has grown large since the country's independence in 1947. Starting from a small base, the pace of growth was initially rapid. Initially, the pace of growth was rapid. Enrolments grew by 13 to 14 per cent per annum during the 1950s and 1960s. Over the past few decades, the growth rate has declined noticeably. Since then it has remained stable between 4 and 5 per cent. The nature of growth over the past two decades is, however, strikingly different from the growth in the previous period. This article maps the growth pattern of higher education in India with particular focus on enrolment growth and change in funding patterns. On analysis of the trends, it identifies the concerns and builds a case for change in Indian higher education so that the country's virtuous cycle of economic growth fuelled mainly by its large pool of qualified manpower is sustained.     

青岛市人力资本与经济增长质量的实证分析

以人力资本溢出模型和有效劳动模型为基础,通过教育年限法分析了青岛市人力资本积累与外溢对经济增长的影响。结果表明,青岛市的经济增长带有明显的资本推动型特征,人力资本的产出弹性和贡献率较低,溢出效应不明显。据此认为,在经济增长方式转型期,青岛应加大教育投入,并制定有效的人才培养和引进机制,以加快人力资本水平的提升。