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51.
超声分散技术在制备小颗粒(Y,Gd)BO_3∶Eu~(3+)粉体中的应用 总被引:1,自引:0,他引:1
采用共沉淀法结合超声分散技术制备亚微米级红色荧光粉(Y,Gd)BO3∶Eu3+,研究了超声时间对离子混合及沉淀过程的影响,以及进而对粉体性能的影响。采用红外光谱(IR)、扫描电子显微镜(SEM)、粉末X射线衍射(XRD)、PDP真空紫外荧光粉测试系统对荧光粉的组成、结构与光学性能等进行表征,结果表明:(Y,Gd)BO3∶Eu3+中[BO3]基团中B原子以四配位为主,同时混有三配位,主体基质YBO3以六方碳钙石结构存在,空间群为P63/mmc(194),晶胞参数a=3.778,c=8.814;在离子混合和沉淀过程中经过超声分散制备的粉体与未经超声分散制备的粉体相比较,相对发光强度提高,色坐标红移(x=0.6392,y=0.3604→x=0.6422,y=0.3575),红橙比(626nm/592nm)提高12%,粒径细小,颗粒形貌均匀,分散性良好。 相似文献
52.
Zinc oxide (ZnO) thin films were grown on n-GaN/sapphire substrates by radio-frequency (RF) magnetron sputtering. The films were grown at substrate temperatures ranging from 400 to 700 ℃ for 1 h at a RF power of 80 W in pure Ar gas ambient. The effect of the substrate temperature on the structural and optical properties of these films was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) spectra. XRD results indicated that ZnO films exhibited wurtzite symmetry and c-axis orientation when grown epitaxially on n-GaN/sapphire. The best crystalline quality of the ZnO film is obtained at a growth temperature of 600 ℃. AFM results indicate that the growth mode and degree of epitaxy strongly depend on the substrate temperature. In PL measurement, the intensity of ultraviolet emission increased initially with the rise of the substrate temperature, and then decreased with the temperature. The highest UV intensity is obtained for the film grown at 600 ℃ with best crystallization. oindent 相似文献
53.
Yang Hua Wang Xiaofeng Ruan Jun Li Zhicong Yi Xiaoyan Duan Yao Zeng Yiping Wang Guohong 《半导体学报》2009,30(9):094002-094002-4
preading layers are analyzed. 相似文献
54.
氧化锌薄膜通过金属有机化学气相沉积方法生长在康宁玻璃与α-蓝宝石衬底上,研究了有关薄膜的生长质量与发光特性.通过X光衍射方法测试研究发现,不仅在以α-蓝宝石为衬底的样品中,同时,在以玻璃为衬底的样品中都发现了氧化锌(0 0 2)方向生长的尖峰,表明生长在两种衬底上的样品都是高度的C向生长.对两种样品的荧光谱研究发现,两者的紫外峰位于374 nm附近,在以α-蓝宝石为衬底的样品中,有深能级发射,但在以玻璃为衬底的样品中没有发现,表明在玻璃衬底上我们生长出了高质量的氧化锌薄膜.通过原子力显微镜,对生长在两种衬底上薄膜的表面形貌做了观察,其晶粒的大小与表面粗糙度有一定的差别,表明二者都是以柱状形式生长的. 相似文献
55.
Y~(3+)掺杂ZnO压敏陶瓷的微结构和电性能研究 总被引:1,自引:0,他引:1
采用两步烧结法制备了Y3+掺杂的(以Y(NO3)3·6H2O形式加入)ZnO压敏陶瓷,通过XRD、SEM和EDX系统研究了Y3+掺杂量对ZnO压敏陶瓷微结构和电性能的影响。结果表明:随着Y3+掺杂量的增加,电位梯度VT和非线性系数α提高,晶粒尺寸减小,施主浓度Nd和晶界态密度Ns降低,势垒宽度ω增大。当掺杂的x[Y(NO3)3·6H2O]为1.2%、烧结温度为1100℃时,ZnO压敏陶瓷电性能最好,其VT为675V/mm,α为63.9,漏电流IL为2.40μA。 相似文献
56.
Shuhai Liu Ming Han Xiaolong Feng Qiuhong Yu Long Gu Longfei Wang Yong Qin Zhong Lin Wang 《Advanced functional materials》2021,31(17):2010339
Utilizing inner-crystal piezoelectric polarization charges to control carrier transport across a metal-semiconductor or semiconductor–semiconductor interface, piezotronic effect has great potential applications in smart micro/nano-electromechanical system (MEMS/NEMS), human-machine interfacing, and nanorobotics. However, current research on piezotronics has mainly focused on systems with only one or rather limited interfaces. Here, the statistical piezotronic effect is reported in ZnO bulk composited of nanoplatelets, of which the strain/stress-induced piezo-potential at the crystals’ interfaces can effectively gate the electrical transport of ZnO bulk. It is a statistical phenomenon of piezotronic modification of large numbers of interfaces, and the crystal orientation of inner ZnO nanoplatelets strongly influence the transport property of ZnO bulk. With optimum preferred orientation of ZnO nanoplatelets, the bulk exhibits an increased conductivity with decreasing stress at a high pressure range of 200–400 MPa, which has not been observed previously in bulk. A maximum sensitivity of 1.149 µS m−1 MPa−1 and a corresponding gauge factor of 467–589 have been achieved. As a statistical phenomenon of many piezotronic interfaces modulation, the proposed statistical piezotronic effect extends the connotation of piezotronics and promotes its practical applications in intelligent sensing. 相似文献
57.
58.
本文利用反射式高能电子衍射(RHEED)、高分辨透射电镜和选区电子衍射方法,系统研究了Si(111)衬底上制备高质量氧化锌单晶薄膜的界面控制工艺.发现低温下Mg(0001)/Si(111)界面互扩散得到有效抑制,形成了高质量的单晶镁膜,进一步通过低温氧化法和分子束外延法实现了单晶MgO缓冲层的制备,从而为ZnO的外延生长提供了模板.在这一低温界面控制工艺中,Mg膜有效防止了Si表面的氧化,而MgO膜不仅为ZnO的成核与生长提供了优良的缓冲层,且极大地弛豫了由于衬底与ZnO之间的晶格失配所引起的应变.上述低温工艺也可用来控制其它活性金属膜与硅的界面,从而在硅衬底上获得高质量的氧化物模板. 相似文献
59.
In this study, ZnO nanoparticles were synthesized based on the chemical reaction of zinc acetate and NaOH in ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) under microwave irradiation. The prepared ZnO were characterized by utilizing various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, FT-IR spectroscopy, and BET method. XRD pattern reveals the produced ZnO has hexagonal structure and the images of SEM and TEM also reveal it consists of nanoparticles with an average size between 15 and 25 nm. The role of the ionic liquid on morphology of ZnO was investigated. For this purpose, a control ZnO sample was prepared without using any [Bmim]Cl. Photocatalytic properties of the synthesized ZnO on degradation of malachite green dye as model pollutant was investigated. The effect of various parameters such as pH, concentration of the dye and catalyst on the degradation of malachite green was investigated. In order to explore the mechanism of photocatalytic degradation of malachite green, scavenger addition method has been employed. It is found that hydroxide radicals are main reactive species for the degradation. 相似文献
60.