水热法合成Zn1-xCoxO室温稀磁半导体

本文采用水热法,在430℃,填充度为35;,3mol/L KOH作为矿化剂,反应时间为24h,合成了Zn1-xCoxO晶体.当在Zn(OH)2中添加一定量的CoCl2·6H2O为前驱物时,水热反应产物中,可以获得多晶体形态的掺杂Zn1-xCoxO晶体.电子探针测量表明,随着前驱物中CoCl2·6H2O添加量的增加,晶体中的Co实际掺入量也随着增加.采用超导量子干涉磁强仪测量材料的磁性,发现在室温以下,水热法合成的Zn1-xCoxO晶体的磁化强度随温度变化很小,在300K存在明显的磁饱和现象和磁滞回线,表明具有室温下铁磁性.     

磁约束电感耦合等离子体增强溅射沉积Co掺杂ZnO薄膜及其光学特性

采用磁约束电感耦合等离子体增强溅射法(ICP-PVD)在Si(100)和石英玻璃衬底上沉积了Zn_0.95Co_0.05O薄膜。XRD谱显示薄膜具有较强的(002)衍射峰,表明Zn_0.95Co_0.05O薄膜为c轴择优取向生长;透过光谱显示Zn_0.95Co_0.05O薄膜具有良好的透过性,其在可见光和红外波段的平均透过率大于80%,吸收光谱表明Co²⁺取代了Zn²⁺处于四配位晶体场中;喇曼光谱证明Zn_0.95Co_0.05O薄膜具有良好的六方纤锌矿结构;室温PL谱测量发现在可见光的蓝光波段和绿光波段存在较宽的发光带,却没有发现本征的近紫外光发射,这是由于Co掺杂后引入较多的缺陷导致的。     

Difference in magnetic properties between Co-doped ZnO powder and thin film

This paper reports that the Zn掺钴;氧化锌粉末;氧化锌薄膜;磁性差异;晶体取向ZnO, Co-doped, crystalline orientation, magnetismProject supported by the Shanghai Nanotechnology Promotion Center (Grant No~0452nm071).2006-09-152006-11-29This paper reports that the Zn0.95Co0.05O polycrystalline powder and thin film were prepared by sol-gel technique under the similar preparation conditions. The former does not show typical ferromagnetic behaviour, while the latter exhibits obvious ferromagnetic properties at 5 K and room temperature. The UV-vis spectra and x-ray absorption spectra show that Co2＋ ions are homogeneously incorporated into ZnO lattice without forming secondary phases.The distinct difference between film and powder sample is the c-axis （002） preferential orientation indicated by the x-ray diffraction pattern and field emission scanning electron microscopy measurement, which may be the reason why Zn0.95Co0.05O film shows ferromagnetic behaviour.     

水热法合成掺Mn橙色刚玉晶体

本文采用水热法,在430℃、40MPa的压力下合成出了纯α-Al2O3晶体.在同样的条件下,通过掺入Mn(NO3)2合成了掺Mn橙红色刚玉晶体.掺入Mn(NO3)2时,合成产物有两种晶体,一种是无色刚玉晶体,体积较小,为六棱柱状,直径30～40μm,高为30～40μm.另一种晶体为橙红色掺Mn刚玉晶体,其外形轮廓近乎球形,晶体表面有十分粗糙的生长阶梯,台阶高度为2～5μm,晶体高200～300μm,直径200～300μm.     

矿化剂浓度对水热法合成氧化锌晶体的影响

In this paper different shapes of ZnO crystals were synthesized by hydrothermal method when different con-centrations of mineralizer were used. When KOH was less than 2mol·L^-1 and the fill factor was approximately 35% at 350℃, ZnO crystals were synthesized with size of several hundred nanometer or several micron. The shapes of crystals were hexagonal cones. When 3mol·L^-1 KOH was used as mineralize at 350℃ and the fill factor was approximately 35%, the crystals with many different sizes were synthesized, the size of maximal crystal was over 100 micron, the small-size crystals were only several micron. When mineralizer KOH was less than 1mol·L^-1 and the fill factor was approximately 35% at 430℃, ZnO crystals were synthesized with size of several hundred nanometer or several micron. The shapes of crystals were hexagonal cones. When 1.5mol·L^-1 KOH or 2mol·L^-1 KOH was used as mineralize at 430℃ and the fill factor was approximately 35%, the high quality and hexagonal prism crystals were synthesized with many different sizes, the size of maximal crystal was over 100 mi-cron, the small-size crystal was only several micron. Especially when 3mol·L^-1 KOH was used as mineralize at 430℃ and the fill factor was approximately 35%, the high quality and hexagonal prism crystals were synthesized with size of 1mm along c axis. The exposed faces were hexagonal faces m{1010}, hexagonal cone faces p{1011}, negative polar faces O{0001}. In addition, many crystals with the shape of hexagonal cone and in several micron to 50 μm of size were present. The exposed faces were hexagonal cone faces p{1011}, negative polar faces {0001}.     

基于元搜索的个性化教学信息推荐系统设计与实现

随着我国教育信息化工作的深入开展,教学资源的迅速膨胀,使得如何从海量教学资源中准确快速地获取所需信息成为教与学过程中急需解决的问题。针对教学信息资源的特点,提出一种基于元搜索技术的面向教学信息推荐系统设计方案和个性化推荐模型,并给出了具体的应用。     

Cu对Zn1－xFexO稀磁半导体磁性的影响

采用水热法，在温度430 ℃，填充度35%，矿化剂为3 mol·L^-1KOH，前驱物为添加适量的FeCl₂·6H₂O的Zn(OH)₂，反应时间24h，合成了Zn_1-xFe_xO和Zn_1-xFe_xO：Cu稀磁半导体晶体.当在Zn(OH)₂中添加一定量的FeCl₂·6H₂O为前驱物，水热反应产物为掺杂Fe的Zn_1-xFe_xO多种形态晶体混合物，其个体较大的晶体中的Fe原子百分比含量为0.49%—0.52%.采用超导量子干涉磁强计测量了材料的磁性，晶体的磁化强度随温度下降而减小.在前驱物中同时加入适量比例的Cu化合物，合成了共掺杂Cu的Zn_1-xFe_xO：Cu，和Zn_1-xFe_xO相比，其室温下的磁化强度有明显的提高，且在室温下具有铁磁性. 关键词： 氧化锌 水热 稀磁半导体 晶体