Epitaxial Silicon Carbide on Silicon. Method of Coordinated Substitution of Atoms (A Review)

Russian Journal of General Chemistry - A review of advances in the growth of SiC epitaxial films on silicon is presented. All the main classical methods used at present to grow SiC films on silicon...     

Limiting Size of Monolayer Graphene Flakes Grown on Silicon Carbide or via Chemical Vapor Deposition on Different Substrates

Russian Journal of Physical Chemistry A - The maximum size of homogeneous monolayer graphene flakes that form during the high-temperature evaporation of silicon from a surface of SiC or during...     

Structures and Properties of Silicon Oxide Clusters by Theoretical Investigations

In this paper, we outline our computational work in the area of silicon oxide clusters. To reduce the computational cost, we designed an economic basis set for silicon oxide systems, and reliable structures were obtained by this approach. To reveal the formation mechanism of silicon nanowires, we investigated the structures and properties of silicon suboxide clusters in particular monoxide clusters that play an important role in the oxide-assisted growth. And to improve our understanding of the silicon dioxide clusters and to bridge the gap between gas phase and solid phase silica, we proposed several models based on the two-membered ring (2MR), three-membered ring (3MR), four-membered ring (4MR), the hybrid of the 2MR and 3MR, or the 3MR and 4MR.     

水热法制备纳米ZnS的光催化性能研究

采用水热法制备了结晶良好的ZnS纳米粒子,通过XRD、FT-IR、TEM、UV-Vis DRS等手段对所合成的ZnS粉体的结构、粒度和理化性能进行表征,并以亚甲基蓝为目标降解物,评价了ZnS粉体在紫外光和可见光下的光催化性能。研究结果表明,水热法制备的纳米ZnS为典型的六方晶系,粒径大致为10～20 nm,不论是在紫外光或可见光下对亚甲基蓝均具有优异的脱色率,呈现出良好的光催化性能。     

Structural and Optical Properties of ZnO Films with Different Thicknesses Grown on Sapphire by MOCVD

IntroductionZnOis one of the most promising materials for pro-ducing ultraviolet laser at room temperature because ofits wide direct band gap(Eg=3.37eV)and large ex-citonic binding energy of60meV.Recently,much at-tention has been paid to short-wavelength …     

绿色化制备纳米木薯渣的微结构与性能

以NaOH、NaClO和H_2O_2为助剂,采用均质、球磨和超声3种机械力相结合的绿色方法对木薯渣(CDs)进行纳米化处理,得到纳米化的木薯渣(NCDs)。利用FT-IR、SEM、AFM、TG、DSC和粒径测试等手段对NCDs进行表征,研究不同助剂及不同工艺对CDs纳米化效果的影响。结果表明:加入15%质量分数的H_2O_2作为助剂,在均质、球磨和超声3种工艺手段共同处理的条件下,CDs纳米化效果最佳,NCDs最小粒径达到30nm,与CDs相比,其稳定性不仅得到提高,而且在悬浮液中的沉降速率变慢。     

Studies on the Properties of ZnO Crystal Plane Grown by the Innovated Hydrothermal Method

ZnO single crystals were grown by the innovated hydrothermal method. The crystal surfaces were polished, and then studied by atom force microscope （AFM） and wet-chemical etching （WCE）. It was found that the Zn polar plane was smoother than O polar plane under the same polishing conditions. The etch pit density of Zn polar plane is 4.3×10^3 cm^-2, which is consistent with the previous report, while the density of etch pit of O polar plane is more than 103cm^-2. After annealing treatment, the density of etch pit of Zn plane reduces to 5.8×102 cm^2 and is superior to the current report. This investigation reveals that the high quality ZnO single crystals with fine Zn polar plane can be obtained by the innovated hydrothermal method.     

Thin Film of Mesoporous MCM-41 Grown on Indium-Tin-Oxide Glass Substrate

ThemesoporousM4lSmaterialshaveattractedconsiderableattentionsincetheywerefirstdiscoveredin19921'2.Thesematerials,amongwhichistheMCM-41molecularsievewithahexagonalarrayofmesopores(diameter15-100A),haveenormouspotentialinapplicationssuchascatalysis',host-guestchemistry'andseparation'.UniformthinfilmsbasedonMCM-417-ichavealsobeenpreparedattheinterfacesofsolution/solidandair/solution.However,thepreviously-reportedfilmsweregrowninvariablyfromanacidicsolutioncontainingsurfactantmoleculesasthest…     

以低熔点金属为催化剂的CVD方法制备硅及硅氧化物纳米材料

<正>一维硅纳米材料由于具有优越的电子学、光学特性以及能够与传统的硅基工业相兼容等特点,使其控制制备倍受科研工作者的关注.在众多一维硅纳米材料的控制合成方法中,经典的气相-液相-固相(VLS)机制下的催化剂诱导生长是一种极为重要的控制合成方法.在VLS机制中,金属催化剂是影响一维纳米结构生长的最重要的因素之一,它     

低温溶胶-凝胶法制备高致密度碳化硅陶瓷工艺研究

以柠檬酸为螯合剂,用溶胶-凝胶法制备碳化硅陶瓷烧结前驱粉体,在烧结助剂含量6%、铝钇摩尔比5/3、1850℃低烧结温度烧结1h条件下,获得了体密度为3.219g/cm3、相对密度为98.3%的高致密烧结体,采用IR、XRD、TG/DTA、SEM/EDS等手段对前驱粉体及烧结体进行了表征,讨论了烧结助剂含量、烧结温度等对碳化硅陶瓷烧结体的收缩率、体密度、失重率等特性的影响。     

Correlating the Morphological Properties and Structural Organization of Monodisperse Spherical Silica Nanoparticles Grown on a Commercial Silica Surface

A variety of nanosilicas have been widely used to fabricate rough surfaces with superhydrophobic and superhydrophilic properties. In this context, we prepared mixed silica and mixed nanosilica that were generated by the growth and self‐assembly of synthesized monodisperse silica nanospheres (11–30 nm, 363 m² g^?1) on the surface of Sylopol‐948 and Dispercoll S3030 by using a base‐catalyzed sol–gel route. Using this process, the interactions and hierarchical structure between the nano‐ and microsized synthesized silica particles were studied by changing the amount of tetraethoxysilane. The resulting materials were characterized by BET analysis, small‐angle X‐ray scattering (SAXS), dynamic light scattering, FTIR spectroscopy, and SEM. The mixed silica presented a higher specific surface area (326 m² g^?1), a six‐fold higher percentage of (SiO)₆ (44–68 %), and a higher amount of silanol groups (14.0–30.7 %) than Sylopol‐948 (271 m² g^?1, 42.6 %, and 12.5 %, respectively). The morphological and hierarchical structural differences in the silica nanoparticles synthesized on the surface of commercial silica (micrometric or nanometric) were identified by SAXS. Mixed micrometric silica exhibited a higher degree of structural organization between particles than mixed nanosilica.     

多孔硅的光电化学特性研究

研究了多孔硅的光电化学特性和溶液中的光致电荷转移机一，由Ｐ型单晶硅制备的多孔硅具有Ｐ型半导体的光电性质，且光电流响应高于单晶硅，由于多孔硅表面态能级对光致电荷的陷阱作用，多孔硅呈现了独特的光电流响应和光致电荷转移性质。     

Structures and Properties of Zn1-xCuxO Nanoparticles by Sol-gel Method

Copper-doped ZnO nanoparticles were synthesized by the sol-gel method.The X-ray diffraction(XRD) result shows that Zn1-xCuxO(x≤0.04) samples are single phase with ZnO-like wurtzite structure,while the secondary phase Cu is observed in a Zn0.95Cu0.05O sample.Magnetic measurements indicate that Zn1-xCuxO(x≤0.04) samples are ferromagnetic at room temperature.A strong green peak(520 nm) was observed except for UV band peak in photoluminescent(PL) spectrum of Zn0.98Cu0.02O.     

稀土氧化物对Si3N4结合SiC制品烧结过程及其性能影响

对Si3N4结合SiC制品进行了掺入稀土氧化物的系统实验, 并对产品进行了X射线衍射测试、常温力学性能测试和扫描电子显微镜观察. 实验结果表明, 稀土氧化物使Si3N4 结合SiC 制品的Si3N4含量提高而氮氧化合物含量明显减少, 使得制品的常温抗折强度与抗压强度都有显著提高. 最后, 从烧结动力学和反应机理等方面初步探讨了掺入稀土的Si3N4结合SiC 制品性能优于普通Si3N4结合SiC制品的原因.