脉冲退火法制备多晶硅薄膜的研究

用射频等离子体化学气相沉积(RF-PECVD)法在普通玻璃衬底上低温制备了μc-Si:H薄膜.采用快速光热退火炉(RTP),分别用低温(＜650℃)和中温(＜750℃)脉冲法(PRTP)对薄膜进行了退火处理.用拉曼光谱和扫描电子显微镜(SEM)研究了不同条件下退火薄膜散射谱的特征和表面形貌.结果显示,脉冲退火法晶化的薄膜,晶化率达到了53;,部分颗粒团簇的尺寸已达到200nm左右.用声子限域理论和表面尺寸效应对薄膜频谱的"红移"和"蓝移"现象进行了分析.     

基于PECVD制备多晶硅薄膜研究

基于PECVD以高纯SiH4为气源研究制备多晶硅薄膜,在衬底温度550℃、射频(13.56MHz)电源功率为20W直接沉积获得多晶硅薄膜.采用X射线衍射仪(XRD) 和场发射扫描电子显微镜(SEM) 对多个样品薄膜的结晶情况及形貌进行分析,薄膜结晶粒取向均为<111>、<220>、<311>晶向.对550℃沉积态薄膜在900℃、1100℃时进行高温退火处理,硅衍射峰明显加强.结果表明,退火温度越高,退火时间越长,得到多晶硅薄膜表面晶粒趋于平坦,择优取向为<111>晶向,晶粒也相对增大.     

铝诱导纳米硅制备大晶粒多晶硅薄膜的研究

本文以超白玻璃为衬底,利用热丝化学气相沉积和磁控溅射法制备了Glass/nc-Si/Al的叠层结构,然后置于管式退火炉中在H2气氛下进行5h诱导晶化,用XRD、光学显微镜、扫描电镜和拉曼光谱对样品进行了表征.结果表明所有样品都是有(111)择优取向的多晶硅薄膜,在425℃诱导时,多晶硅晶粒尺寸最大达400 μm,但薄膜不连续;随着诱导温度升高到450℃,样品表面已形成了连续的多晶硅薄膜,但晶粒尺寸有所减小;475℃下诱导获得的最大晶粒尺寸约为200μm,此时多晶硅薄膜的结晶质量更好.还从动力学的角度分析了铝诱导纳米硅的晶化机理.     

铝诱导表面织构玻璃及其对硅薄膜陷光作用的影响

采用铝诱导表面织构方法在玻璃衬底上制备了蜂窝状的凹坑结构;使用热丝化学气相沉积技术在该类衬底上制备了硅薄膜.扫描探针显微镜(SPM)图像表明,通过改变刻蚀时间、刻蚀溶液比例、Al膜厚度和退火时间等制备条件,可以有效控制玻璃表面凹坑结构的尺寸,使其在直径上从0.5μm到6μm,深度上从60 nm到700 nm可调.光吸收谱测试表明此类衬底对硅薄膜的光吸收有着明显的增强效果,以凹坑平均直径为2.3 μm,深度为358nm的铝诱导表面织构玻璃为衬底所制备的厚度为150 nm的硅薄膜,在350～1200 nm波长范围内的光吸收与使用平面玻璃为衬底的样品相比可提高28.5;.凹坑的尺寸大小对光吸收增强效果有重要影响.     

热丝法低温制备多晶硅薄膜微结构的研究

采用热丝化学气相沉积法(HFCVD)在普通玻璃衬底上低温沉积多晶硅薄膜。利用XRD、拉曼光谱和原子力显微镜(AFM)研究了灯丝与衬底间距(5~10mm),灯丝温度(1800~1400℃)和衬底温度(320~205℃)对薄膜晶体取向、晶化率、晶粒尺寸以及形貌的影响规律。结果表明,随着热丝与衬底间距增加,多晶硅薄膜的晶化率和晶粒尺寸明显减小;随热丝温度的降低,薄膜的晶化率都出现了大致相同的规律:先不断增大后突然大幅减小。     

卷对卷技术制备大面积柔性CIGS薄膜太阳电池吸收层

以轻质柔性聚酰亚胺(PI)材料为衬底,采用低温共蒸发"一步法"工艺制备四元化合物Cu(In,Ga)Se2(CIGS)薄膜.本文采用卷对卷(roll-to-roll)技术,在衬底幅宽300 mm的方向上实现了良好的成膜均匀性.利用XRD和XRF分别分析了所制备薄膜的晶相、组分和厚度,SEM分析了薄膜的表面形貌,讨论了不同衬底温度下制备的CIGS薄膜的性能.     

AIC多晶硅薄膜的制备与其上HWCVD低温外延生长多晶硅薄膜的研究

铝诱导晶化法(AIC)是一种低温制备大晶粒多晶硅薄膜的重要方法.本文分别基于Al/Al2O3/a-Si叠层和a-Si/SiOx/Al叠层制备了AIC多晶硅薄膜,前者表面粗糙,后者表面光滑.以后者为籽晶层,在其上用HWCVD法300℃低温下外延生长了表面形貌与籽晶层相似的多晶硅薄膜.铝诱导晶化过程中,在原始非晶硅层中会形成多晶硅、非晶硅和铝的混合层,去除铝后残留的硅将使表面粗糙,而在原始铝层中则形成连续的多晶硅薄膜.Al/Al2O3/a-Si 叠层和a-Si/SiOx/Al叠层的上层分别是非晶硅层和铝层,发生层交换后,前者上层是硅铝混合层,因此表面粗糙,后者上层是连续的多晶硅薄膜,因此表面光滑.在AIC多晶硅薄膜表面外延生长多晶硅薄膜等效于铝诱导多晶硅的晶核在垂直于薄膜方向上的继续生长,因此外延生长的薄膜与AIC多晶硅薄膜呈现相似的枝晶状形貌.     

AIT玻璃衬底非晶硅薄膜的固相晶化研究

本实验在铝诱导织构的基础上,对以AIT浮法玻璃为衬底沉积非晶硅薄膜固相晶化进行了初步研究.采用拉曼散射、X射线衍射等手段对生成多晶硅薄膜的结构和光学性能进行了表征和分析.研究结果表明:热处理10h,薄膜的晶化率达到80;以上,同时具有良好的(111)择优取向;同平板玻璃衬底对比,AIT玻璃上制备的多晶硅薄膜具有良好的陷光作用.     

电场辅助铝诱导晶化非晶硅薄膜

以氢气稀释的硅烷和氢气为反应气体,利用PECVD法先在玻璃衬底上生长非晶硅薄膜,然后利用磁控溅射法在非晶硅薄膜上镀制铝膜,最后将镀有铝膜的非晶硅薄膜样品置于快速热处理炉中,在外加电场辅助条件下,在氮气气氛下对薄膜样品进行退火制备多晶硅薄膜.本论文研究了不同外加电场强度和退火时间对非晶硅薄膜晶化的影响.利用XRD、SEM和Raman等测试方法对薄膜样品的晶相结构、表面形貌和晶化程度进行了表征.实验结果表明,在外加横向电场辅助铝诱导晶化的条件下,非晶硅薄膜在500 ℃低温下成功地转化成多晶硅薄膜,并且随着横向电场强度的增大以及退火时间的延长,薄膜的晶化程度增强,晶粒尺寸增大.     

利用快速热退火法制备多晶硅薄膜

为了制备优质的多晶硅薄膜,该论文研究了非晶硅薄膜的快速热退火(RTA)技术.先利用PECVD设备沉积非晶硅薄膜,然后把其放入快速热退火炉中进行退火.退火前后的薄膜利用X射线衍射(XRD)仪、Raman光谱仪及扫描电子显微镜(SEM)测试其晶体结构及表面形貌,利用电导率测试设备测试其暗电导率.研究表明退火温度、退火时间以及沉积时的衬底温度对非晶硅薄膜的晶化都有很大的影响.     

First-principles coexistence simulations of supercooled liquid silicon

We perform first-principles coexistence simulations of the low-density and the high-density phases of supercooled liquid silicon and find a negative slope for the coexisting line in the temperature-pressure plane. Electron density maps and electron-localization function plots of the two phases of silicon show marked differences. The calculated differences suggest more localized electrons in the low-density liquid compared to the high-density liquid, coming from an increased population of covalent bonds, which further explain the calculated negative slope in the two phase coexistence regime. This is consistent with the presence of a pseudo-gap in low-density liquid silicon, absent in the high-density liquid which shows a metallic behavior.     

Triethyl ammonium salt of O,O′-bis(p-tolyl)dithiophosphate, [Et3NH]+[(4-MeC6H4O)2PS2]−

Triethyl ammonium Salt of O,O′-bis(p-tolyl)dithiophosphate and O,O′-bis(m-tolyl)dithiophosphate have been obtained by reaction of p- and m-cresol, respectively with P₂S₅ in toluene and have been characterized by elemental analysis, IR, ¹H and ³¹P NMR spectroscopy. The molecular structure of O,O′-bis(p-tolyl)dithiophosphate has been determined. Crystal data: [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻: Monoclinic, P2₁/c, a=15.2441(9) ?, b=10.415(2) ?, c=3.9726(9) ?, β=91.709(7)°, V=2217.5(1) ?⁻³, Z=4.Supplementary materials Additional material available from the Cambridge Crystallographic Data Centre (CCDC no. 600927 for [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻ comprises the final atomic coordinates for all atoms, thermal parameters, and a complete listing of bond distances and angles. Copies of this information may be obtained free of charge on application to The Director, 12 Union Road, Cambridge CB2 2EZ, UK (fax: +44-1223-336033; email: deposit@ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk).     

Crystal structures of thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane

Structures of both thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane, ?C₆H₄?CH₂SCH₂?C₆H₁₀?CH₂SCH₂?, have been determined, wherecis andtrans refer to the attachments to the cyclohexane ring. Thecis form crystallizes in the monoclinic space groupP2₁/c witha=8.4299(11)Å,b=21.772(2)Å,c=8.9724(13)Å, β=116.574(11)^o, andZ=4. Thetrans isomer packs into the monoclinic space groupP2₁ witha=8.159(16)Å,b=10.185(5)Å,c=9.558(2)Å, β=112.435(18)^o, andZ=2. The cyclohexane ring of thecis isomer is in the chair conformation, while the cyclohexane of thetrans isomer is found in a twisted boat conformation.     

CTAB与SDBS对碳酸锶粒子生长形态调控及机理研究

以表面活性剂CTAB和SDBS为化学添加剂,采用化学共沉淀法对碳酸锶晶体的生长形态进行调控,成功地制备出了实心的树枝状和花瓣为空心的花状碳酸锶粉体,并用X射线衍射(XRD)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FT-IR)等分析手段对样品进行了表征;最后重点对化学添加剂可能产生的影响机理进行了初步的探讨.结果表明,CTAB和SDBS在晶体生长的过程中能起到显著的影响作用,两者对粒子分散性能的作用效果相反,而且后者对晶体(013)和(213)晶面表面能降低的贡献明显大于前者.     

Crystal structure of Zn4Na(OH)6SO4Cl·6H2O

The structure of Zn₄Na(OH)₆SO₄Cl·6H₂O, a secondary mineral from Hettstedt, Germany, was determined by single-crystal X-ray diffraction. The crystals are hexagonal,a=8.413(8),c=13.095(24) Å, space group $P\bar 3$ , Z=2. The structure was refined to R=0.0554 and R_w=0.0903 for 970 reflections with I≥3σ(I). The structure can be described as zinc hydroxide layers perpendicular toc, from which sulfates and chlorides extend. The layers are held together by a system of hydrogen bonds involving hexaaquo Na⁺ ions which occupy the interlayer space.     

Crystal structures of the cis and trans isomers of a tetrathia[3.3.3.3]cyclophane

Both the cis and trans isomers of 3,11,18,26-tetrathiatricyclo[26.2.2.1^5,9.2^13,16.1^20,24] hexatriaconta-5,7,9,20,22,24-hexene have been prepared and structurally characterized. Each of these centrosymmetric tetrathia dimers includes two cyclohexane rings in chair conformations with either 1,4-cis or 1,4-trans bonding and two meta-substituted benzene rings. The cis isomer packs into the monoclinic space group P2₁/a with a = 10.485(3)Å, b = 10.3956(18)Å, c = 14.1343(10)Å, = 105.200(13)°, Z = 2 and refined to an R factor of 0.046. The trans isomer crystallizes in the monoclinic space group P2₁/c with a = 10.7217(12)Å, b = 5.6797(7)Å, c = 25.415(5)Å, = 96.001(12)°, Z = 2 and refined to an R factor of 0.043. In the cis structure each benzene ring faces a cyclohexane ring while in the trans structure the cyclohexane rings face one another.     

Synthesis and Crystal Structure of 5-[2-(6-bromonaphthalenyloxymethyl)]-3-(4-morpholinomethyl)-1,3,4-oxadiazole-2(3<Emphasis Type="Italic">H</Emphasis>)-thione

Abstract  The title compound, C₁₈H₁₈BrN₃O₃S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) ?, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal] reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these angles which therefore play a role in stabilizing crystal packing. Graphical Abstract  Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C₁₈H₁₈BrN₃O₃S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Crystal structure of irisolidone from the flowers of Pueraia lobata

Irisolidone (5,7-dihydroxy-6,4′-dimethoxyisoflavone) was isolated from the flowers of Pueraia lobata and its crystal structure was examined by X-ray single crystal diffraction. The crystal structure of irisolidone is monoclinic, space group P2₁/c with a = 15.491(9) ?, b = 7.895(4) ?, c = 13.321(7) ?, β = 110.546(9)° and Z = 4. Hydrogen bonding and aromatic π–π stacking assemble the title compound into a three-dimensional networking structure.     

电沉积法制备ZnO纳米棒阵列及其发光特性

本文以掺F的SnO2导电玻璃为基板,以硝酸锌水溶液为电解液,采用三电极恒电位体系电沉积制备ZnO纳米棒阵列,系统考察了硝酸锌浓度和沉积电位等工艺参数对ZnO纳米棒阵列的微观形貌及其发光性能的影响规律.结果表明,硝酸锌浓度和沉积电位对纳米棒阵列的形貌有显著影响,控制适宜的工艺条件可以制备出直径分布均匀、结晶性好且纯度高的六方纤锌矿ZnO纳米棒阵列.荧光光谱分析表明,电沉积制备出的ZnO纳米棒阵列在385 nm附近有一个强荧光发射峰,且发光性能稳定、对纳米棒阵列微观形貌的细微变化不敏感,使其在发光二极管和激光器等领域具有广阔的应用前景.