衬底温度对直流磁控溅射法制备掺锆氧化锌透明导电薄膜性能的影响

利用直流磁控溅射法在石英衬底上制备出了高透明导电的掺锆氧化锌(ZnO:Zr)薄膜.研究了衬底温度对ZnO:Zr薄膜结构、形貌及光电性能的影响.XRD表明实验中制备的ZnO:Zr为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向.实验所制备ZnO:Zr薄膜的晶化程度和导电性能对衬底温度有很强的依赖性.当衬底温度为300 ℃时, ZnO:Zr薄膜具有最小电阻率7.58×10-4 Ω·cm,其可见光平均透过率超过了91;.     

Al-H共掺杂ZnO薄膜的形貌及光致发光性能研究

在不同衬底温度条件下采用RF磁控溅射法在石英玻璃上沉积Al-H共掺杂ZnO薄膜.对所有样品进行晶体结构、表面形貌、电学、光学以及室温光致发光性能分析.结果表明:随着衬底温度的升高,ZnO薄膜的结晶度增加,晶粒增大,薄膜致密度增加;薄膜表面起伏变化减小;同时,电阻率最低达到7.58×10-4Ω·cm,透过率保持在75;左右.所有ZnO薄膜样品都以本征发光为主,Al-H共掺杂在一定程度降低ZnO薄膜缺陷发光的强度;随着衬底温度的升高,ZnO薄膜的本征发光强度明显增大;同时在能量为3.45 eV附近观察到了一个紫外发光峰.     

超声喷雾热分解法制备ZnO薄膜及衬底温度对其性能的影响

以醋酸锌水溶液为前驱体溶液,采用超声喷雾热分解法在玻璃衬底上制备得到了温度在350℃到450℃范围内的ZnO薄膜.用X射线衍射(XRD)、扫描电镜(SEM)及紫外-可见分光光度计分析了ZnO薄膜的晶体结构、微观形貌及其光学性质,重点探究了衬底温度对ZnO薄膜生长过程及微观结构的影响.分析表明:制备的ZnO薄膜为六角铅锌矿结构,衬底温度对薄膜的质量有着重要的影响;所得薄膜在400℃时结晶性能好,沿c轴择优取向生长,具有优良的均匀性和致密性;所制备的薄膜在可见光区透过率高达86;以上,在紫外光区吸收强烈.     

工艺参数对飞秒激光沉积硅基ZnO大面积均匀薄膜性能的影响

研究了衬底温度、真空度、激光能量、激光脉冲频率及退火处理对飞秒激光制备硅基ZnO大面积均匀薄膜的结构和性能的影响.结果表明,当激光能量为1.5mJ、脉冲频率为400 Hz、真空度为1.0 mPa、衬底温度为80℃时,所制备的薄膜质量最佳.薄膜呈高度c-轴取向,为典型的六方纤锌矿结构,晶粒沿垂直于衬底表面的方向生长;当衬底温度高于80℃时,随着温度的升高,c-轴取向度降低.80℃制备的薄膜在可见紫外区域透过率达98;,电阻率随温度升高而减小,退火后薄膜的透过率增大、电阻率升高.     

超声喷雾热解法制备CeO2薄膜及性能研究

以硝酸铈(Ce(NO3)3·6H2O)水溶液为前驱溶液,采用自制超声喷雾热解装置在石英衬底上沉积制备CeO2薄膜,并通过X射线衍射(XRD)、扫描电镜(SEM)、紫外可见分光光度计等分析薄膜晶体结构、微观形貌及光学特性.结果表明,随着沉积温度升高,薄膜择优生长取向逐渐变为(200);当沉积温度为500℃时,薄膜具有良好的致密性;薄膜在可见光区表现出近85;的高透过率,同时发现随着沉积温度升高,薄膜透过率逐渐增大,光吸收逐渐由缺陷吸收转变为本征吸收.     

靶与衬底之间的距离对ZnO∶Zr透明导电薄膜性能的影响

利用直流磁控溅射法在室温玻璃衬底上制备出了可见光透过率高、电阻率低的掺锆氧化锌(ZnO∶Zr)透明导电薄膜。并系统地研究了靶与衬底之间的距离对ZnO∶Zr薄膜结构、形貌、光学及电学性能的影响。实验结果表明,靶与衬底之间的距离对ZnO∶Zr薄膜的生长速率、结晶质量及电学性能有很大影响,而对其光学性能影响不大。实验制备的ZnO∶Zr为六方纤锌矿结构的多晶薄膜,且具有垂直于衬底方向的c轴择优取向。当靶与衬底之间的距离从60 mm减小到50 mm时,薄膜的晶化程度提高、晶粒尺寸增大,薄膜的电阻率减小;然而,当距离继续减小时,薄膜的晶化程度降低、晶粒尺寸减小,薄膜的电阻率增大。当靶与衬底之间的距离为50 mm时,薄膜的电阻率达到最小值4.2×10-4Ω.cm,其可见光透过率超过95%。实验制备的ZnO∶Zr薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极。     

衬底温度对硼掺杂ZnO薄膜微观结构及其光电特性的影响

采用射频磁控溅射技术,改变玻璃衬底温度制备B掺杂ZnO薄膜,薄膜的微结构及其光电性能分别用X-射线衍射仪、紫外-可见分光光度计、四探针测试仪及粗糙度测试仪进行表征.结果表明:ZnO∶B薄膜样品表面平整,具有六角纤锌矿结构并呈C轴择优取向.所有薄膜样品在420 ～ 900 nm区间内的平均透光率大于91;.随着温度的增加,电阻率先减小后增大,但晶粒尺寸一直变大.衬底温度为100℃时电阻率可低至1.14×10-3Ω·cm,所有样品禁带宽度相对于本征ZnO蓝移.     

退火对电弧离子镀制备的ZnO薄膜的影响

采用阴极电弧离子镀在Si、Al2O3以及玻璃衬底上制备出具有择优取向的ZnO薄膜,并对其进行退火处理.利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、光致发光光谱(PL)、紫外-可见光光谱仪对ZnO薄膜的结构、表面形貌和光学性能进行分析.XRD结果表明,所制备的ZnO薄膜具有很好的ZnO(002)择优取向,退火使ZnO(002)衍射峰向高角度方向偏移.SEM结果表明,随着退火温度升高,表面晶粒由隆起的山脉或塔状变为平面状,晶粒002面呈六边状.PL谱结果表明,随着退火温度的升高,紫外发光峰强度逐渐增强,可见光发光峰强度逐渐相对减弱.紫外可见光透过谱结果表明,退火使可见光透过率增高,光学带隙发生红移.     

利用直流磁控溅射法在柔性衬底上制备ZnO: Zr新型透明导电薄膜

室温下利用直流磁控溅射法在有ZnO缓冲层的柔性衬底 PET上制备出了可见光透过率高、电阻率低的掺锆氧化锌(ZnO: Zr)透明导电薄膜,研究了厚度对ZnO: Zr薄膜结构及光电性能的影响.结果表明,ZnO: Zr薄膜为六方纤锌矿结构的多晶薄膜.实验获得ZnO: Zr薄膜的最小电阻率为2.4×10-3 Ω·cm,其霍尔迁移率为18.9 cm2·V-1·s-1 ,载流子浓度为2.3×1020 cm-3.实验制备的ZnO: Zr薄膜具有良好的附着性能,其可见光平均透过率超过92;.     

衬底温度对磁控溅射法制备掺Ta氧化锌薄膜性能的影响

采用射频磁控溅射法,在不同的衬底温度下制备了钽(Ta)掺杂的氧化锌(ZnO)薄膜,采用X射线能谱(EDS)、X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见分光光度计和光致发光(PL)光谱研究了衬底温度对制备的Ta掺杂ZnO薄膜的组分、微观结构、形貌和光学特性的影响.EDS的检测结果表明,Ta元素成功掺入到了ZnO薄膜;XRD图谱表明,掺入的Ta杂质是替代式杂质,没有破坏ZnO的六方晶格结构,随着衬底温度的升高,(002)衍射峰的强度先增大后降低,在400℃时达到最大;SEM测试表明当衬底温度较高时(400℃和500℃),Ta掺杂ZnO薄膜的晶粒明显变大;紫外-可见透过光谱显示,在可见光范围,Ta掺杂ZnO薄膜的平均透光率均高于80;,衬底不加热时制备的Ta掺杂ZnO的透光率最高;制备的Ta掺杂ZnO薄膜的禁带宽度范围为3.34~3.37eV,衬底温度为500℃时制备的Ta掺杂ZnO薄膜的禁带宽度最小,为3.34eV.PL光谱表明衬底温度为500℃时制备的Ta掺杂ZnO薄膜中缺陷较多,这也是造成薄膜禁带宽度变小的原因.     

Relationship of Morphological Types of Dynamic Forms of Crystals

Crystallography Reports - The relationship of morphological spectra (sets of data on the morphological types of real polyhedral crystals and their probabilities under current physicochemical...     

Development of Pauling's concepts of geometric characteristics of atoms

The evolution of the geometric characteristics introduced by Pauling and their dependence on the specific features of the structure and chemical bonds have been considered. The values of the covalent and van der Waals radii are given as well as their relationships and mutual transitions.     

A review of measurement of thermophysical properties of silicon melt

Measurements of thermophysical properties of Si melt and supplementary study of X-ray scattering/diffraction by the authors' group were reviewed. The values obtained differed variously from those of literature. Density was 2–3% larger, surface tension 20–30% smaller, viscosity up to 40% larger, electrical conductivity 8% smaller, spectral emissivity more or less in good agreement with literature values, and thermal diffusivity a few percent larger. An anomalous density jump was found near the melting point. Surface tension and viscosity also showed anomaly. A strange time-dependent change of density was observed over 3 h after melting. X-ray analyses suggested a slight change in local atom ordering, but showed no sign of cluster formation. An addition of 0.1 at% gallium caused the density jump to disappear, while that of boron caused no change. An EXAFS study of the former melt indicated a strong interaction between Ga and Si atoms as if molecules of GaSi₃ existed. The implications of the measured properties are a possibility of soft-turbulence in an Si melt in a relatively large crucible, a more complicated manner of intake of oxygen depleted molten Si from the free surface region to underneath the growing crystal, and a relaxation of the melt after melting arising from trapped gas species.     

Generation of crystal structures of heteromolecular compounds by the method of discrete modeling of packings

Within the method of discrete modeling of packings, an algorithm of generation of possible crystal structures of heteromolecular compounds containing two or three molecules in the primitive unit cell, one of which has an arbitrary shape and the other (two others) has a shape close to spherical, is proposed. On the basis of this algorithm, a software package for personal computers is developed. This package has been approved for a number of compounds, investigated previously by X-ray diffraction analysis. The results of generation of structures of five compounds—four organic salts (with one or two spherical anions) and one solvate—are represented.     

Investigation of the Mechanism of Influence of Stress Corrosion on the Development of Macroplastic Instabilities of Aluminum–Magnesium Alloy

Crystallography Reports - Macroscopic jumps of plastic deformation (few percent in amplitude) on creep curves of aluminum–magnesium alloy, caused by a local effect of concentrated solution of...     

Velocities of Disappearance and Lifetime of Faces of Growing Crystals

The formulae for absolute R_disap and relative R velocities of disappearance and lifetime τ of faces of growing crystals have been derived for stationary growth. It was shown that the quantities are determined by the relative growth velocity R_A/R_critA of the vanishing face A with respect to the critical growth velocity R_critA and by the geometry of a crystal expressed by the trigonometric functions of interfacial angles β and γ formed between face A and the adjacent faces. R increases and τ decreases with the increase in R_A/R_critA to certain limiting values. The calculations have been verified and illustrated by the experimental results for triclinic potassium bichromate (KBC) crystals. Results enable ones to predict values of velocities of disappearance and lifetimes of undesirable, supplementary faces of any real crystal.     

Comparative analysis of two methods of calculation of the orientation of domain walls in ferroelastics

Two types of domain-wall equations are analyzed: the equations derived by the Sapriel method and the equations obtained by interface matching of the thermal-expansion tensor. It is shown that, for W-type domain walls, these methods yield the same equations. For W′-type domain walls, the equations obtained by different methods coincide for proper ferroelastics and differ for improper ferroelastics.     

Dependence of the parameters of equations of viscous flow on chemical composition of silicate melts

The temperature dependence of viscosity of silicate melts is discussed in the framework of the Avramov–Milchev (AM) equation. The composition is described by means of two parameters: the molar fraction, x, and the “lubricant fraction”, l. The molar fraction is the sum of the molar parts x_i of all oxides dissolved in SiO₂, the molar fraction of the latter being 1 ? x. It is shown that, with sufficient precision, two of the parameters of the AM equation can be presented as unique functions of the molar fraction. On the other hand, x is not sufficient to determine properly the reference temperature T_r , at which viscosity is η_r = 10¹³ [dPa.s]. Therefore, additional parameter, “lubricant fraction” l, is introduced. For each of the components, l_i is a product of molar part x_i and a specific dimensionless coefficient 0 ≤ k_i ≤ 1 accounting for the specific contribution of this component to the increased mobility of the system. It is demonstrated that, for l > 0, the reference temperature is related to the “lubricant fraction” l through the reference temperature T_r,SiO2 of pure SiO₂.     

Mechanism of thermal expansion of structural modifications of zinc pyrovanadate

Crystal chemical characteristics of the α and β modifications of Zn₂V₂O₇ are calculated based on in situ high-temperature X-ray measurements. The expansion of the structure is found to be strongly anisotropic up to the negative volumetric thermal expansion of the α-Zn₂V₂O₇ unit cell in the temperature range of 300–600°С, α _V =–17.94 × 10^–6 1/K. The transformations of the “hard” and “soft” sublattices with an increase temperature and at the phase transition are considered in detail. It is shown that the negative volumetric thermal expansion of α-Zn₂V₂O₇ is due to the degeneracy of the zigzag-like shape of zinc–oxygen columns at constant distances between their vertices.