ZnSe微球的制备与性能研究

采用水热法,以ZnSO4·7H2O为Zn源,Na2SeO3为Se源,NaOH溶液为反应介质,N2H4·H2O为还原性助剂,在140℃下反应24 h,合成了直径为1～4μm、分散性较好的ZnSe微球.SEM、XRD和UV-Vis测试发现,NaOH和N2H4·H2O共同控制着ZnSe的形貌,制备的ZnSe微球是由平均尺寸为20.7 nm的ZnSe纳米晶在N2微泡上聚集而成的中空球.     

单质直接气相生长ZnSe单晶

本文直接以高纯Zn、Se单质为原料,加入少量碘单质作为反应输运剂,用化学气相输运(CVT)的方法一步成功的生长出了ZnSe单晶.采用XRD、EDS、紫外可见分光光度计和光致发光(PL)技术研究了生长的ZnSe晶体的结构、成份以及光学特性.结果表明,生长的ZnSe单晶具有较好结晶性能,成份接近理想的化学计量比,在500～2000nm范围内透过率达到65;～70;,在1.9～2.5 eV范围内存在与Zn空位和杂质能级相关的发光带.由Zn和Se单质在输运剂I2的辅助下一步直接生长ZnSe单晶是可行的.     

微乳液法制备不同形貌低维硒化锌纳米晶

利用微乳液法,实现了多晶硒化锌纳米空心球、单晶硒化锌纳米棒以及ZnSe量子点的低温合成.通过调整Triton X-100/环己烷/水体系中表面活性剂Triton X-100的浓度分别制备出直径在120 nm左右,壁厚在6nm左右的ZnSe多晶纳米空心球体、长度达1μm的单晶纳米棒和直径位于4～6nm的ZnSe量子点.紫外可见吸收光谱显示不同形貌ZnSe纳米结构的吸收特征具有较大的差别.     

低温合成PSN微球及其裂解制备Si-C-N空心陶瓷微球

以含乙烯基聚硅氮烷(PSN)为先驱体聚合物,二乙烯基苯(DVB)为交联剂,采用乳液工艺,在低温条件下交联固化合成聚硅氮烷(PSN)微球,并在高温下裂解制得Si-C-N空心陶瓷微球.研究了原料比例、固化时间和裂解条件对PSN微球及Si-C-N空心陶瓷微球形貌、尺寸和形成过程的影响.结果表明,当PSN与DVB的比例为2∶1、固化时间为6h时,可在80℃下得到表面光滑、尺寸较均匀、直径为600～ 800 nm的PSN微球;Si-C-N陶瓷微球随着PSN与DVB比例的增加,逐渐显现出空心结构;1000～ 1200℃裂解后,空心球形成,XRD表明此时产物呈非晶态;裂解温度1400℃时,空心微球表面变得粗糙,生成Si3N4和SiC晶粒.     

片状ZnSe纳米材料的溶剂热法制备及表征

采用溶剂热法,对制备的前驱体进行热处理,最后得到了片状结构的ZnSe纳米材料.然后利用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM))和光致发光谱(PL)等测试手段对样品的晶体结构、形貌、微结构和光学性质等进行了表征分析.结果表明制备的ZnSe块状结构是由厚度大约在200 ～300 nm纳米带堆叠而成,其晶体结构为密排六方晶体结构.此外,通过分析反应过程,对片状ZnSe生成过程中的可能的化学反应和片状ZnSe可能的形成机理做了简单的分析.     

Cr2+∶ZnSe中红外激光晶体生长及光谱性能

采用物理气相输运法( PVT),以Cr2+∶ ZnSe多晶为原料,在源区温度约为1000℃、温差为6～7℃条件下生长2周,获得了体积约为0.7 cm3的Cr2+∶ZnSe晶体.紫外-可见-近红外透过光谱显示,Cr2+∶ZnSe样品在1770nm左右出现了强吸收;Cr2+浓度在1019 atoms/cm3数量级,与原料中Cr2+浓度基本一致,反映了较低温度PVT法生长有利于获得预期的Cr2+掺杂浓度.荧光测试结果表明,Cr2+∶ZnSe样品谱线对称性好,发射峰位约在2400 nm,线宽约600 nm;室温荧光寿命为5.52×10-6s.数据分析结果表明,Cr2+∶ZnSe样品的吸收截面和发射截面峰值分别为1.1×10-18cm2和2.3×10-18 cm2.     

CVT一步生长的ZnSe单晶的光电特性研究

本文采用化学气相输运(CVT)法,由Zn(5N)和Se(5N)一步直接生长了片状ZnSe单晶,并对其结构特性和光电性能进行分析。研究表明,生长出的ZnSe单晶仅显露(111)面,红外透过率约为40%～42%,具有较高的结晶质量。该ZnSe单晶可与In电极形成良好的欧姆接触,其体电阻率约为7.3×109Ω.cm。     

水热法制备类花状MoS2纳米纸微球

采用水热合成技术,以钼酸钠、硫脲为反应剂,草酸为助还原剂,去离子水为溶剂,合成了类花状结构的MoS2纳米纸微球,采用X射线衍射仪(XRD)、拉曼光谱、透射电镜(HRTEM)、扫描电子显微镜(SEM)和X射线能量色散谱(EDS)对样品的结构、形貌和成分进行分析,重点研究了草酸浓度对MoS2纳米纸微球的形貌和结构的影响规律.结果表明:在适当的反应剂浓度下,合成的MoS2是由大量厚度约30 nm左右的纳米纸花瓣聚集在一起形成的类花状微球组成的.MoS2微球具有2H型六方晶系结构,而每片纳米纸花瓣是单晶结构的层状MoS2.反应前驱液中草酸的浓度对微球的大小、形貌和结晶度有显著的影响.最后讨论了类花状结构的MoS2纳米纸微球的生长机理.     

硒化锌的化学机械抛光研究

采用化学机械抛光(CMP)的方法,自制抛光液作为研磨介质,对(50×50×1.5)mm3硒化锌(ZnSe)晶片抛光.通过分析抛光液的pH值、抛光盘转速、抛光液的磨料浓度、压力、抛光时间和抛光液流量等参数对CMP的影响,组合出最佳工艺参数,并通过原子力显微镜和平晶测试方法对最佳工艺参数获得的ZnSe晶片进行测试,实验结果显示,ZnSe晶片抛光后的表面粗糙度Ra为0.578 nm,平面面形误差小于1.8 μm.     

纳米结构四氧化三铁空心微球的合成及磁性研究

用乙二醇为溶剂,三氯化铁和尿素为起始反应试剂,通过水热反应合成了Fe3O4空心微球.用X射线衍射仪(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)表征样品的结构和形貌,结果表明,所制备的单分散Fe3O4空心微球为立方单晶结构,其直径约400 nm,是由纳米颗粒组装而成.用振动样品磁强计(VSM)测量了Fe3O4空心微球的室温磁性,发现其表现为铁磁性.     

Novel route to scalable synthesis of II–VI semiconductor nanowires: Catalyst-assisted vacuum thermal evaporation

Vacuum thermal evaporation, a conventional film fabricating technique, has been explored to synthesize II–VI semiconductor nanowires based on a catalyst-assisted vapor–liquid–solid (VLS) process. Low melting-point metals, such as bismuth and tin, can be used as catalysts by co-evaporating with desired semiconductor materials. As proof of the concept, CdTe, CdS, ZnSe and ZnS single crystalline nanowires have been successfully synthesized on a large scale by this method. The growth mechanism involved in the method has been discussed. Morphological, structural and optical properties of as-synthesized nanowires were characterized, revealing the high quality of the nanowires. The results indicate that the method presented here is a novel and general route to mass production of II–VI semiconductor nanowires, which can be possibly scaled up for industrial application at low cost, and extended to other material systems.     

Hydrothermal synthesis of ZnSe hollow micropheres

ZnSe hollow spheres aggregated from nanoparticles with size of 60∼100 nm have been successfully synthesized via simple hydrothermal routes. NaOH and cetyltrimethyl ammonium bromide (CTAB) were used to control the shape and size, respectively. The as‐prepared microspheres were characterized with powder X‐ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV‐vis spectroscopy. The results indicate that the products are well dispersed and uniform. The effect of two additives was discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Preparation and characterization of ordered mesoporous silica membrane

Hexagonal mesoporous silica (MCM-41) membranes were prepared at air-water interface by means of an interfacial silica-surfactant self-assembly process. The free-standing and oriented mesoporous silica membranes with pore size ≈2.9-3.8 nm were synthesized at room temperature in acidic media and were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) observations. Small-angle X-ray diffraction (SAXRD) patterns of membranes clearly indicated that as-synthesized membranes were typical of MCM-41 materials with a periodic hexagonal structure with the channels parallel to the surface. SEM images showed that the as-synthesized membrane was continuous and crack-free. In this paper, some novel findings are reported.     

ZnSe薄膜的化学反应辅助热壁外延法生长及特性研究

本文通过将新型化学气相反应促进剂Zn(NH4)3Cl5引入到热壁外延系统中,以二元素单质Zn和Se为原料,直接在Si(111)衬底上生长了高质量的ZnSe晶体薄膜,薄膜成分接近理想化学计量比。研究了主要工艺参数对薄膜生长形貌和性能的影响。采用SEM、AFM、EDS和PL谱技术研究了生长的ZnSe薄膜的形貌、成分和发光特性。研究结果表明,热壁温度和生长时间是影响ZnSe薄膜形貌的主要因素;气相反应促进剂在薄膜生长和调节成分方面扮演了关键角色,Zn(NH4)3Cl5的存在使得Zn(g)和Se2(g)合成ZnSe晶体的反应转变为气固非一致反应,从而更容易获得近乎理想化学计量比的ZnSe薄膜。ZnSe薄膜在氦镉激光激发下,室温下PL谱由近带边发射和(VZn-ClSe)组合的SA发光组成,而在飞秒激光激发下,仅在481nm处显示出强烈的双光子发射峰。     

Large-scale synthesis of ZnSe nanoribbons on zinc substrate

ZnSe nanoribbons have been successfully synthesized on a large scale by solvothermal treatment of Zn and Se powder in the mixture of hydrazine hydrate and diethanolamine at 140 °C for 24 h and subsequent annealing in Ar. The morphology of the final products strongly depended on the volume ratio of hydrazine hydrate and diethanolamine. Scanning electron microscopy (SEM) explorations indicated that the as-prepared ZnSe nanoribbons were mostly about 40 nm in thickness, 100 nm in width, and 50 μm in length. X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM) investigations confirmed that resulting ZnSe nanoribbons are wurtzite structures and have a [0 0 1] growth direction. PL (photoluminescence) spectrum of the products exhibited a visible light emission. Based on these investigations, the products were expected to find wide applications in optoelectronic, field emission and catalytic fields.     

Structure and photoluminescence properties of SrWO4 3D microspheres synthesized by the surfactant‐assisted hydrothermal method

In this paper, we report large‐scale high‐quality SrWO₄ 3D microspheres synthesized in aqueous solutions under mild conditions with cetyl trimethyl ammonium bromide as a simple cationic surfactant. These crystals have been characterized by X‐ray diffraction, transmission electron microscopy and field emission scanning electron microscopy techniques. The crystal growth processes were employed to investigate the formation mechanism of SrWO₄ 3D microspheres. Room‐temperature photoluminescence indicated that the as‐prepared SrWO₄ 3D microcrystals had strong emission peaks at about 432 and 505 nm, respectively.     

单源真空蒸发法制备ZnSe薄膜的实验研究

本文采用单源真空蒸发法制备了ZnSe薄膜,利用电子探针、X射线粉晶衍射等现代测试手段研究了蒸发温度(700～1050 ℃)、基片温度(0～200 ℃)、基片材料(单晶硅、玻璃)以及热处理温度(300～400 ℃)等因素的改变对ZnSe薄膜的成份和结构的影响规律,建立了单源真空蒸发沉积ZnSe薄膜及热处理的实验方法.     

铁硅分子筛Fe-Silicalite-1催化剂的一步合成与应用

利用一步水热合成法,在有机模板剂1,6-己二胺结构导向作用下,合成了具有MFI骨架结构的铁硅酸盐分子筛晶体Fe-Silicalite-1.并通过XRD、TG-DTA、IR和SEM等测试方法对其结构和性能进行了表征.ICP-AES及EDS分析结果表明:Fe原子进入到分子筛骨架上,质量分数约为0.66;.在以过氧化氢为氧化剂,羟化苯酚的催化反应中,苯酚的转化率为22.2;,其中65.8;为邻苯二酚,34.2;为对苯二酚.Fe-Silicalite-1分子筛晶体是一种良好的合成二酚的催化剂,具有潜在的应用价值.     

Synthesis of monodisperse platinum nanoparticles supported on carbon gel microspheres

Monodisperse platinum nanoparticles were successfully fabricated on the porous structure of carbon gel microspheres with a narrow pore size distribution. The size of the platinum nanoparticles supported on the carbon gel microspheres was almost coincident with the pore size of the carbon gel microspheres. The results indicated the potential for controlling the size distribution of the supported platinum nanoparticles using the carbon gel microspheres with different pore size distributions.