Effects of preparation parameters on growth and properties of β-Ga2O3 film

The Ga$_{2}$O$_{3}$ films are deposited on the Si and quartz substrates by magnetron sputtering, and annealing. The effects of preparation parameters (such as argon-oxygen flow ratio, sputtering power, sputtering time and annealing temperature) on the growth and properties ($e.g.$, surface morphology, crystal structure, optical and electrical properties of the films) are studied by x-ray diffractometer (XRD), scanning electron microscope (SEM), and ultraviolet-visible spectrophotometer (UV-Vis). The results show that the thickness, crystallization quality and surface roughness of the $\beta $-Ga$_{2}$O$_{3}$ film are influenced by those parameters. All $\beta $-Ga$_{2}$O$_{3 }$films show good optical properties. Moreover, the value of bandgap increases with the enlarge of the percentage of oxygen increasing, and decreases with the increase of sputtering power and annealing temperature, indicating that the bandgap is related to the quality of the film and affected by the number of oxygen vacancy defects. The $I$-$V$ curves show that the Ohmic behavior between metal and $\beta $-Ga$_{2}$O$_{3}$ films is obtained at 900 ${^\circ}$C. Those results will be helpful for the further research of $\beta $-Ga$_{2}$O$_{3}$ photoelectric semiconductor.     

双辉等离子体表面冶金金属化CVD金刚石自支撑膜研究

采用双辉等离子表面冶金技术,在金刚石自支撑膜表面制备了W金属层.借助扫描电子显微镜(SEM)、能谱仪(EDS)和X-射线衍射仪(XRD)等分别对金属化后的金刚石膜的微观形貌、元素分布及物相组成进行了表征与分析;并通过测试Ag-Cu钎焊的金刚石膜-硬质合金刀片样品的剪切强度,评价金属层与金刚石膜的结合强度.实验结果表明:所制备的W金属层连续、致密,由大量纳米尺度的颗粒状团聚物构成;在金属层与金刚石界面一定深度区域内,存在W和C元素的相互扩散,并且反应生成了WC、W2C等金属碳化物颗粒,表明金属层与金刚石膜之间已形成了牢固的化学键合.     

绝缘体中金属离子注入合成纳米颗粒的理论研究

理论上提出了利用离散电子态来计算绝缘体中金属纳米颗粒Fermi能级的方法,给出了金属纳米颗粒的能级结构,并得到了依据金属纳米颗粒等离子体共振峰计算金属纳米颗粒尺寸的新公式.该理论可解释相关现象,通过实验初步验证了该理论的正确性. 关键词： 离子注入 金属纳米颗粒 绝缘体 Fermi能级     

基于聚酰胺6纳米纤维膜的固相萃取-高效液相色谱法测定兔血浆中酮康唑对映体

以基于聚酰胺6纳米纤维膜的固相萃取法,结合高效液相色谱手性流动相添加剂法测定了兔血浆中的酮康唑对映体的浓度。仅用1.5mg聚酰胺6纳米纤维膜、100μL甲醇即可完成目标物的富集和洗脱。酮康唑的2个对映体在50.0～400.0μg/L范围内呈良好的线性;方法的定量限为40.0μg/L;日内和日间精密度分别小于6.3%和8.6%;平均绝对回收率为79.4%～85.6%;平均相对回收率为90.0%～96.5%。本方法灵敏、准确、重现性好,符合生物样本中酮康唑对映体分析测定的要求。     

Effect of metal nanoparticle doping concentration on surface morphology and field emission properties of nano-diamond films

Nano-diamond particles are co-deposited on Ti substrates with metal (Ti/Ni) nanoparticles (NPs) by the electrophoretic deposition (EPD) method combined with a furnace annealing at 800℃ under N₂ atmosphere. Modifications of structural and electron field emission (EFE) properties of the metal-doped films are investigated with different metal NPs concentrations. Our results show that the surface characteristics and EFE performances of the samples are first enhanced and then reduced with metal NPs concentration increasing. Both the Ti-doped and Ni-doped nano-diamond composite films exhibit optimal EFE and microstructural performances when the doping quantity is 5 mg. Remarkably enhanced EFE properties with a low turn-on field of 1.38 V/μm and a high current density of 1.32 mA/cm² at an applied field of 2.94 V/μm are achieved for Ni-doped nano-diamond films, and are superior to those for Ti-doped ones. The enhancement of the EFE properties for the Ti-doped films results from the formation of the TiC-network after annealing. However, the doping of electron-rich Ni NPs and formation of high conductive graphitic phase are considered to be the factor, which results in marvelous EFE properties for these Ni-doped nano-diamond films.     

孤子中的再激发研究

本文在准一维紧束缚近似下,研究了孤子中的再激发。得到 , ,, , , 。其中 , 和 分别代表中性孤子、带电孤子和带电极化子, 表示链中出现的扭结。     

工艺参数对高功率MPCVD金刚石膜择优取向的影响研究

使用自行研制的椭球谐振腔式MPCVD装置,以H2-CH4为气源、沉积功率8 kW条件下,在不同CH4浓度、沉积温度和气体流量工艺条件下制备了大面积金刚石膜.使用X射线衍射仪对金刚石膜的择优取向的变化规律进行了研究.实验结果表明,高功率条件下工艺参数对金刚石膜的择优取向有不同程度的影响.在CH4浓度由0.5;上升到1.0;时,金刚石膜的择优取向由(220)转变为(111),由1.O;上升到2.5;时,则由(111)转变为(220)以及(311);在700 ～ 1050℃温度范围内,随着沉积温度的升高,金刚石膜(111)择优取向生长的倾向增高,当沉积温度高于1050℃时,金刚石膜改变了原先的以(111)择优取向生长的趋势,变为了以(100)择优取向生长;在气体流速为200～1000 sccm范围内时,随气体流量的增加,金刚石膜(111)择优取向的倾向增加.当气体流量大于1000sccm时,金刚石膜(111)择优取向的倾向又稍有降低.     

侧链型液晶聚合物对手性向列相液晶螺旋结构的影响研究

通过改变表面的锚定条件,可以在不借助外部条件的情况下获得热力学稳定态的长程有序的螺旋结构.通过调节沉积在硅晶片上的液晶聚合物[6-(4-甲氧基-偶氮苯-4'-氧基)甲基丙烯酸乙酯](PMMAZO)的接枝密度来调节表面锚定,从而实现对螺旋结构的螺距和螺旋方向的准确控制.随着接枝密度的增加,螺旋结构的倾斜变形增加,螺距的大小被抑制;随着液晶盒厚度的增加,形态会从长程有序的条纹状逐渐过渡到指纹状.     

四氢呋喃/三氟化硼乙醚混合电解质中咔唑的电化学聚合

在四氢呋喃/三氟化硼乙醚混合电解质中直接阳极氧化咔唑制备聚咔唑.单体的起始氧化电位为0.92 Vversus SCE,远低于单体在含0.1 mol.L-1Bu4NBF4的乙腈溶液中的起始氧化电位(1.36 Vversus SCE).在此体系中获得的聚咔唑膜具有良好的电化学活性和稳定性,其电导率为7.0×10-3S.cm-1.聚合物可部分溶解于二甲基亚砜等强极性有机溶剂.UV-Vis,FT-IR,1H-NMR证明聚合物共轭长链的形成.该体系中获得的聚咔唑是一种蓝光发射材料,并具有良好的热稳定性.