用脉冲激光沉积方法制备的ZnO薄膜的结构及光致发光特性

在从室温到800℃的温度范围内,用脉冲激光沉积方法在Al₂O₃（0001）衬底上制备了ZnO薄膜。采用X射线衍射仪、原子力显微镜以及荧光光谱仪分别研究了衬底温度对ZnO薄膜表面形貌、结晶质量和光致发光特性的影响。X射线衍射仪和原子力显微镜的结果表明,当衬底温度从室温升高到400℃时,ZnO薄膜的结构及结晶质量逐渐提高,而当衬底温度超过400℃时,其结构和结晶质量变差;在400℃下生长的ZnO薄膜具有最佳的表面形貌和结晶质量。室温光致发光的测量结果表明,400℃下生长的ZnO薄膜的紫外发光强度最强,且发光波长最短（386 nm）。     

三氧化二铁外延薄膜的制备及贯穿位错表征

氧化物薄膜中贯穿位错的类型和密度对其物理与化学性质具有重要影响。本文利用脉冲激光沉积技术在Al₂O₃(0001)和SrTiO₃(111)衬底上分别生长了α-Fe₂O₃外延薄膜，并利用X射线衍射、原子力显微镜和透射电子显微术对不同温度下生长的薄膜其相结构、结晶度、表面形态和位错类型等进行了系统的表征。结果表明：生长温度对Al₂O₃衬底上薄膜的质量影响很小，而对SrTiO₃衬底上薄膜的质量影响显著，Al₂O₃衬底上薄膜的结晶度和表面平整度普遍优于SrTiO₃衬底上的薄膜；Al₂O₃衬底上薄膜中的贯穿位错为■刃型不全位错，而SrTiO₃衬底上薄膜中的贯穿位错不仅包含■刃型不全位错，还有■混合型全位错。     

高k材料镧前驱体La(tmhd)3和La(tmod)3的热力学及其ALD应用

通过同步热分析研究两种不同的前驱体(La(tmhd)₃和La(tmod)₃)在升华过程中的热稳定性。结果表明,具有不对称分子结构的La(tmod)₃的挥发性大于La(tmhd)₃,其可以作为镧前驱体应用于原子层沉积(ALD)技术。将La(tmod)₃和O₃作为前驱体,通过ALD技术在SiO₂基片上实现了LaO_x薄膜的制备。实验结果表明,其最佳的ALD工艺参数包括：La(tmod)₃和O₃的脉冲时间分别为6 s和2 s, O₃的清洗时间为5 s,沉积温度为250℃。在制备的薄膜中发现了理想的自限性沉积行为。通过X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)和原子力显微镜(AFM)证实了生长的薄膜具有良好的纯度和表面形貌,其在250℃的沉积温度下具有稳定的生长速率(约0.16?/cycle, 1?=0.1 nm),薄膜的主要成分为La_...     

脉冲激光沉积法制备ZnSnO_3薄膜

采用脉冲激光沉积法(PLD),在Pt/Ti/SiO_2/Si衬底上制备LiNbO_3型ZnSnO_3薄膜。通过改变生长过程中的氧气压、生长温度等实验条件,研究制备薄膜的最佳工艺参数。利用X射线衍射仪(XRD)、原子力显微镜(AFM)和扫描电子显微镜(SEM)对薄膜进行分析。研究表明,在Pt/Ti/SiO_2/Si衬底上制备ZnSnO_3薄膜优化条件是氧气压30 Pa、沉积温度600℃,并使用ZnO作为缓冲层。优化条件下制备的ZnSnO_3薄膜有良好的(006)取向,与ZnSnO_3单晶衍射峰位置一致。     

CVD法制备的高结晶质量二维β-Ga2O3薄膜性质研究

为了能够得到高质量的薄膜,降低实验成本,通过化学气相沉积(CVD)方法以GaTe粉作为Ga源在云母衬底上合成了β-Ga₂O₃薄膜。通过改变生长温度、载气和生长时间得到高结晶质量的β-Ga₂O₃薄膜,并通过X射线衍射(XRD)和拉曼光谱进行证实。XRD结果显示,薄膜的最佳生长温度为750℃。对比不同载气下合成的β-Ga₂O₃薄膜可知,Ar气是生长薄膜材料的最佳环境。为了实现高结晶质量的β-Ga₂O₃薄膜,在Ar气环境下改变薄膜的生长时间,XRD结果发现,生长时间20 min的薄膜具有高结晶质量。最后,将其转移到300 nm厚氧化层的Si/SiO₂衬底上,并通过原子力显微镜测试,证实了16 nm厚的二维Ga₂O₃薄膜。     

Ag/La0.67Sr0.33MnO3薄膜电阻开关特性的研究

采用脉冲激光沉积技术在SrTiO3（001）单晶衬底上制备出钙钛矿结构La0.67Sr0.33MnO3薄膜，利用X射线衍射仪与原子力显微镜表征其晶体结构与微观形貌，并对Ag/La0.67Sr0.33MnO3/SrTiO3结构的室温电脉冲诱发可逆变阻效应进行了分析讨论。该效应表现出良好的非挥发多值存储特性，有望应用于新型存储器、传感器、可变电阻等电子元器件的研制。     

Ag/La_(0.67)Sr_(0.33)MnO_3薄膜电阻开关特性的研究

采用脉冲激光沉积技术在SrTiO3(001)单晶衬底上制备出钙钛矿结构La0.67Sr0.33MnO3薄膜,利用X射线衍射仪与原子力显微镜表征其晶体结构与微观形貌,并对Ag/La0.67Sr0.33MnO3/SrTiO3结构的室温电脉冲诱发可逆变阻效应进行了分析讨论。该效应表现出良好的非挥发多值存储特性,有望应用于新型存储器、传感器、可变电阻等电子元器件的研制。     

Ag/La0.67Sr0.33MnO3薄膜电阻开关特性的研究

采用脉冲激光沉积技术在SrTiO3(001)单晶衬底上制备出钙钛矿结构La0.67Sr0.33MnO3薄膜,利用X射线衍射仪与原子力显微镜表征其晶体结构与微观形貌,并对Ag/Lao.67Sr0.33MnO3/SrTiO3结构的室温电脉冲诱发可逆变阻效应进行了分析讨论.该效应表现出良好的非挥发多值存储特性,有望应用于新型存储器、传感器、可变电阻等电子元器件的研制.     

超声喷雾热解法制备 TiO2 薄膜

成功地利用超声喷雾热解法在玻璃衬底上制备了TiO2薄膜。Ti（SO4）2作为钛源,甲醇作为溶剂。利用超声波的雾化作用将反应物形成细小的雾滴,并喷射到预热的玻璃衬底上分解而形成稳定的TiO2薄膜。为获得致密均匀的薄膜,优化了反应物浓度、温度、沉积时间等参数。利用X射线衍射与原子力显微镜表征了薄膜的晶体结构与表面形貌。X射线结果表明薄膜为多晶锐钛矿结构TiO2薄膜,并在（101）方向呈现出择优趋势。     

脉冲激光沉积系统（PLD）的应用——制备GaN薄膜

采用脉冲激光沉积技术,在Al2O3衬底上生长GaN薄膜,利用X射线衍射(XRD)、原子力显微镜(AFM)研究不同沉积温度、不同沉积压强对所生长的GaN薄膜晶体结构特征的影响。研究表明,在750℃的沉积温度时,GaN薄膜的结晶质量较高;在20 Pa以下的沉积气压下,GaN薄膜的晶体质量随着沉积气压的升高而提高。     

VOLTE容灾机制研究及优化方案

_{本文首先对VOLTE现网网络结构及容灾机制进行研究分析,发现现存容灾机制中存在的缺点和不确定性,针对其中的问题,针对性地进行了深入研究和分析,创新的提出了1种快速容灾抢通方案,以达到提升VOLTE业务运维能力和用户业务感知的目的。}     

Calculation of energy band gaps in quaternary iii/v alloys

The dielectric theory of electronegativity is applied to the calculation of the compositional dependence of the energy band gap for quaternary III/V alloys of type A_l-xB_xC_1-yD_y and A_1-x-yB_xC_yD. The departure from linearity of E_G versus x and y is taken to be the sum of two terms, the intrinsic or virtual crystal term and the extrinsic term due to effects of aperiodicity which for one type of alloy may occur on both sublattices. Rather than simply treating the quaternary as an average of the bounding ternary systems, as has been common in the past, the intrinsic departure from linearity is calculated by assuming E_h,i,C, and D_av to vary linearly with x and y. The result is a smaller intrinsic deviation from linearity and a much better fit to existing data in the system Ga_1-xIn_xAs_1-y P_y. The calculation is also applied to three systems where no data exist but which are of great interest because of their potential application for the fabrication of lattice matched tandem solar cells: Ga_l-xA1_xAs_l-ySb_y. Ga_1-x-yA1_xIn_yAs, and GaAs_1-x-yP_xSb_y.     

新形势下河北移动全业务支撑策略研究

随着铁塔公司的成立及国家在“宽带中国”“提速降费”等一系列通信领域的重大战略实施,全业务运营越来越成为河北移动保持领先,实现卓越的重要支点。基于此河北移动启动大规模综合业务区建设,由传统传输网围绕基站建设转向全业务支撑。河北移动将综合业务区建设与全业务机房的选取统筹安排,建设综合业务区与全业务机房的联络光缆,将综合业务区光缆网成为承载重要集客数据专线和4G拉远站的载体,合理、有序、迅速实现“一张光缆网”的建设,鼎力支撑全业务及4G的发展。     

Nickel silicidation techniques for strained Si1?xGex, Si1?x?yGexCy, and Si1?yCy alloys material-device applications

A nickel silicide process for Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy materials compatible with Si technology has been developed. Low-resistivity-phase (12–20 μΘ cm) nickel silicides have been obtained for these alloys with different low sheet-resistance temperature windows. The study shows that thin (15–18 nm) silicide layers with high crystalline quality, smooth silicide surface, and smooth interface between silicide and the underlying material are achievable. The technique could be used to combine the benefits of Ni silicide and Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloys. The technique is promising for Si or Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy-based metal-oxide semiconductor, field-effect transistors (MOSFETs) or other device applications.     

Low pressure metalorganic chemical vapor deposition of InP and related compounds

The low pressure metalorganic chemical vapor deposition epitaxial growth and characterization of InP, Ga_0.47In_0.53 As and Ga_xIn_1-xAs_yP_1-y, lattice-matched to InP substrate are described. The layers were found to have the same etch pit density (EPD) as the substrate. The best mobility obtained for InP was 5300 cm² V⁻¹S⁻¹ at 300 K and 58 900 cm² V⁻¹ S⁻¹ at 77₂K, and for GaInAs was 11900 cm² V⁻¹ S⁻¹ at 300 K, 54 600 cm² V⁻¹ S⁻¹ at 77 K and 90 000 cm V⁻¹S⁻¹ at 2°K. We report the first successful growth of a GaInAs-InP superlattice and the enhanced mobility of a two dimensional electron gas at a GaInAs -InP heterojunction grown by LP-MO CVD. LP MO CVD material has been used for GaInAsPInP, DH lasers emitting at 1.3 um and 1.5 um. These devices exhibit a low threshold current, a slightly higher than liquid phase epitaxy devices and a high differential quantum efficiency of 60%. Fundamental transverse mode oscillation has been achieved up to a power outpout of 10 mW. Threshold currents as low as 200 mA dc have been measured for devices with a stripe width of 9 um and a cavity length of 300 um for emission at 1.5 um. Values of T in the range 64–80 C have been obtained. Preliminary life testing has been carried out at room temperature on a few laser diodes (λ = 1.5μm). Operation at constant current for severalthousand hours has been achieved with no change in the threshold current.     

Characterization of a rapid thermal anneal TiNxOy/TiSi2 contact barrier

In this paper, the physical and electrical properties of a TiN_xO_y/TiSi₂ dual layer contact barrier are reported. The TiN_xO_y/TiSi₂ barrier was formed by rapidly annealing a Ti thin film on Si in an N₂ ambient. During this process, the Ti film surface reacts with N₂ to form a TiN_xO_y skin layer and the bulk of the Ti film reacts with Si to form an underlying TiSi₂ layer. The influences of rapid thermal anneal (RTA) conditions on the TiN_xO_y layer were investigated by varying the RTA temperature from 600 to 1100° C and cycle duration from 30 to 100 s. It is found that the resulting TiN_xO_y and TiSi₂ layer thicknesses are dependent on RTA temperature and the starting Ti thickness. For a starting Ti thickness of 500Å, 150Å thick TiN_xO_y and 800Å thick TiSi₂ are obtained after an RTA at 900° C for 30 s. The TiN_xO_y thickness is limited by a fast diffusion of Si into Ti to form TiSi₂. When a Ti film is deposited on SiO₂, Ti starts to react with SiO₂ from 600° C and a significant reduction of the SiO₂ thickness is observed after an RTA at 900° C. The resulting layer is composed of a surface TiN_xO_y layer followed by a complex layer of titanium oxide and titanium suicide. In addition, when Ti is depos-ited on TiSi₂, thicker TiN_xO_y and TiSi₂ layers are obtained after RTA. This is because the TiSi₂ layer retards the diffusion of Si from the underlying substrate into the Ti layer. NMOSFETs were fabricated using the TiN_xO_y/TiSi₂ as a contact barrier formed by RTA at 900° C for 30 s and a significant reduction of contact resistance was obtained. In addition, electromigration test at a high current density indicated that a significant improvement in mean time to failure (MTF) has been obtained with the barrier.     

Transport properties of thermoelectric materials for coolers

The Seebeck coefficient, thermal conductivity, electrical conductivity and Hall coefficient of cooler grade, p-and n-type ternary alloys of Bi₂Te₃-Sb₂Te₃-Sb₂Se₃ were measured between 10 and 300 K. Between 300 K and about 150 K the temperature dependence of the transport properties can be explained by assuming nondegeneracy and a lattice scattering mechanism. The difference between the temperature dependence of the Hall effect in n-and p-type alloys can be explained by the presence of sub-bands of light and heavy holes in the valence band of p-type alloys.     

Processing of large YBa2 Cu3Ox domains for levitation applications by a Nd1+x Ba2−x Cu3 Oy-Seeded melt-growth technique

YBa₂Cu₃O_x domains for levitation applications have been produced by a seeding technology that includes Nd_1+x Ba_2−x Cu₃O_y seeds and melt-processing technologies such as conventional melt-textured growth, melt-texturing with PtO₂ and Y₂BaCuO₅ additions, and the new solid-liquid-melt-growth technology. Large domains (∼20 mm) with high levitation forces (F₁ up to 8.2 N) have been produced. The reproducibility of the results is good, and the capability of producing a large number of pellets in a single batch indicates good potential for the production of large amounts of this material.     

基于InP衬底的晶格失配In0.68Ga0.32As的MOCVD生长及其特性研究

采用MOCVD生长技术在InP衬底上成功实现了晶格失配的3μm In0.68 Ga0.32As薄膜生长.通过As组分的改变,利用张应变和压应变交替补偿的InAsxP1-x应变缓冲层结构来释放由于晶格失配所产生的应力,在InP衬底上得到了与In0.68Ga0.32 As晶格匹配的InAsxP1-x“虚拟”衬底,通过对缓冲层厚度的优化,使应力能够在“虚拟”衬底上完全豫弛.通过原子力显微镜(AFM)、高分辨XRD、透射电镜(TEM)和光致发光(PL)等测试分析表明,这种释放应力的方法能够有效提高In0.68 Ga0.32 As外延层的晶体质量.     

The effect of Tl2Te3 on the properties of the solid solution (Sb2Te3)0.75.(Bi2Te3)0.25

The effect on transport properties of the addition of 0.5-5% Tl₂Te₃ to p-type solid solutions of antimony and bismuth tellurides was studied. It was found that the addition of Tl₂Te₃ caused a lessening of the increase of hole concentration as low temperatures were approached, resulting in a slower decrease of the Seebeck coefficient with a decrease in temperature. In partial fulfillment of M.Sc. degree, Hebrew University, Jerusalem. Permanent address, Dept. of Inorganic and Analytical Chemistry, Hebrew University, Jerusalem.