掺Gd-CdTe薄膜的XPS研究

应用双源法真空蒸发制备掺Gd的CdTe薄膜,并借助XPS对其进行组份分析。实验表明,Gd掺杂的CdTe薄膜的组分为Cd、Te、O、C、Gd等元素,其中C、O主要以物理吸附方式存在于薄膜表面;Cd、Te元素的存在方式为CdTe化合物及其氧化物形式;而Gd元素由于碳污染的原因在其表面未曾出现,只在刻蚀过程中出现;深度剥蚀分析表明在样品内部Cd元素的含量大于Te元素的含量,且接近于1∶0.8,趋于稳定。     

Pr掺杂CdS薄膜的制备及其光电性能研究

结合化学水浴法和真空电子束热蒸发法在玻璃衬底上制备了含有不同厚度Pr掺杂层的CdS多晶薄膜,并对薄膜的结构、表面形貌和光电特性进行了研究。结果表明,未掺杂的CdS薄膜为沿[111]晶向择优生长的立方相闪锌矿结构,导电类型为N型。Pr掺杂并未改变CdS薄膜的物相结构和择优取向,但衍射峰强度增加;掺Pr后CdS薄膜的晶粒尺寸增大,致密性提高,并且薄膜在可见光范围内的透过率增加,光学带隙变大。同时还发现CdS中掺Pr后影响了薄膜的电学性能,掺杂浓度较低时CdS薄膜电阻率增大,掺杂浓度较高时薄膜的电阻率降低并且导电类型由N型转变为P型。     

La_2O_3掺杂对ZnO-B_2O_3-SiO_2玻璃熔体物性及成玻能力的影响

为研究氧化镧掺杂对55ZnO-40B_2O_3-5SiO_2系玻璃熔体粘度及成玻能力的影响,采用熔融退火法制备了添加不同La_2O_3含量(0.5%,1.0%,1.5%,2.0%)的锌硼硅玻璃。利用红外光谱、高温旋转粘度计、差示扫描量热法和热膨胀测定法对玻璃的结构和性能进行表征。结果表明,氧化镧掺杂量从0上升到1.0%的过程中,玻璃中的[BO_3]向[BO_4]转化,使结构致密,粘度升高,成玻能力增大;但在氧化镧由1.0%上升到2.0%的过程中,玻璃中的[BO_4]向[BO_3]转化,使结构疏松,粘度下降,成玻能力减小。     

La掺杂TiO_2薄膜的制备与光生阴极保护研究

采用溶胶凝胶法利用浸渍提拉技术在430不锈钢基片上制备了纯TiO_2与La掺杂TiO_2薄膜。利用XRD、SEM、EDS、XPS等测试技术对样品进行晶型结构、表面形貌和元素组成的表征分析;采用Tafel曲线对薄膜耐腐蚀性能进行测试。结果表明,La掺杂没有改变TiO_2晶型结构,二者均为锐钛矿,La掺杂有细化晶粒的作用;La掺杂TiO_2薄膜更加均匀致密;光照时,薄膜都有一定的光生阴极保护作用,La掺杂TiO_2薄膜的光生阴极保护作用优于纯TiO_2薄膜。     

Dy掺杂对ZnSe薄膜微结构的影响

利用真空蒸发的方法制备ZnSe多晶薄膜,并采用双源法对薄膜进行了Dy的掺杂.用XRD、紫外可见分光光度仪对薄膜的性质进行了表征.结果表明,当Zn、Se原子配比为0.9:1时可制备较理想的ZnSe多晶薄膜,稀土Dy掺杂并未改变样品的物相结构,但掺杂使薄膜的晶格常数及晶胞体积略有增大,还使得薄膜的晶粒尺寸及压应力变小,掺杂...     

钨掺杂氧化锌薄膜的结构与光学性能的研究

实验采用溶胶-凝胶法在石英玻璃衬底上制备了掺杂不同钨离子浓度氧化锌薄膜.研究了钨离子的浓度变化对氧化锌薄膜结构与光学性能的影响.测试结果表明,钨离子的掺入使氧化锌薄膜的晶体质量得到提高,衍射峰位置向低衍射角度方向移动,导致薄膜的光学带边发生收缩,即产生＂红移＂现象.随着钨离子浓度增加,氧化锌薄膜光致发光强度表现为先增加而后出现浓度淬灭现象.     

Dy掺杂ZnTe薄膜的结构及光学特性

利用真空蒸发的方法制备ZnTe多晶薄膜,并采用双源法对薄膜进行了稀土元素Dy的掺杂.用XRD、紫外可见分光光度仪对薄膜的性质进行了表征.结果表明,当原子配比Zn:Te=1:0.7,热处理温度T=500℃时,可制备较理想的ZnTe多晶薄膜.稀土Dy掺杂并未改变样品的物相结构,但使薄膜光吸收增大而光学带隙减小.     

钆掺杂TiO_2纳米管的制备及光致发光性能研究

采用溶胶-凝胶法及500℃煅烧工艺制备了纯的和不同Gd掺杂量的TiO_2纳米粉,并以其为前驱物,通过微波水热合成法制备了相应的TiO_2纳米管,利用场发射扫描电镜(FESEM),场发射透射电镜(FETEM),X射线衍射(XRD)和荧光光谱(FS)仪等对样品进行表征,考察不同Gd的掺杂量对TiO_2纳米粉及纳米管形貌、结晶度和光致发光性能的影响。结果表明,纯的TiO_2纳米粉为15 nm左右,随着Gd掺杂量的提高,煅烧后TiO_2纳米粉粒径降低;当Gd含量为2%时,TiO_2纳米粉粒径减小到10 nm左右。纯的和掺杂Gd的TiO_2纳米管形貌均为两端开口,内中空,管的直径为8 nm左右,长度为100~500 nm,说明Gd掺杂含量对TiO_2纳米管的形貌影响不大。XRD分析表明,TiO_2纳米管的结晶度普遍低于纳米粉的结晶度,而适当Gd元素掺杂使TiO_2纳米管能保持一定的结晶度。另外,Gd掺杂量也影响TiO_2纳米粉以及纳米管的FS信号强度。随着Gd掺杂量的增加,TiO_2纳米管的FS信号强度有先增加后降低的变化趋势,当Gd掺杂量为0.5%和0.2%时,TiO_2纳米管的FS信号强度达到最大值。     

退火对AlCN非晶薄膜结构及力学性能的影响

利用磁控溅射方法在单晶硅基片上制备出不同Al含量AlCN非晶薄膜,随后分别在700℃和1000℃进行真空退火热处理.使用X射线衍射仪和高分辨透射电镜研究了沉积态和退火态薄膜的组织和微观结构,用纳米压痕仪测试硬度和弹性模量.结果表明,退火态薄膜组织和微观结构强烈依赖于薄膜的Al含量.经1000℃退火后,低Al含量AlCN薄膜没有出现结晶现象,但形成了分层;高Al含量AlCN薄膜中,退火促使AlN纳米晶的生成,使薄膜形成了非晶包裹纳米晶的复合结构,随着距表面深度的增加,形成的纳米晶密度和尺寸均有减小的趋势.随着退火温度的升高,AlCN薄膜的硬度和弹性模量均降低;而对于高Al含量AlCN薄膜,由于形成了纳米复合结构,硬度和弹性模量下降幅度减少.     

Gdx((Fe83Co17)55Ag45)100-x颗粒膜结构及巨磁电阻效应研究

复合靶以Fe,Co,Ag和Gd按一定比例组成,采用磁控溅射法制备了Gdx((Fe83Co17)55Ag45)100-x(x=0,3.5,5.0,6.5,8.0,9.5)颗粒膜。在室温下,利用X射线衍射仪(XRD)、四探针电阻测试仪、振动样品磁强计(VSM)等方法研究Gd的掺入以及不同退火温度对颗粒膜显微结构、巨磁电阻效应(GMR)和磁性能影响。X射线衍射实验结果表明:薄膜形成了以Ag(111)和FeCo(110)组成的合金结构,且增加稀土Gd的掺入量能促进薄膜基体中FeCo与Ag的相分离。磁电阻测试结果发现:不同成分的Gdx((Fe83Co17)55Ag45)100-x(x=0,3.5,5.0,6.5,8.0,9.5)薄膜样品均随着退火温度升高以及稀土Gd含量增加,颗粒膜巨磁电阻(GMR)效应呈现先增后减的趋势,且饱和场逐渐降低,当x=5.0、退火温度250℃时,Gd5.0((Fe83Co17)55Ag45)95.0薄膜巨磁电阻效应达到最大,GMR值为-14.8%。Gd掺杂后样品磁滞回线的变化表明薄膜的矫顽力较小,矩形比随Gd含量的增加而增加,分析认为Gdx((Fe83Co17)55Ag45)100-x薄膜具有良好的软磁性能。     

Relationship between Crystal Structure and Luminescence Properties of （Y0.96-x Lnx Ce0.04 ）3 Al5 O12 （LH=Gd,La, Lu） Phosphors

The doping effects of La^3＋, Gd^3＋ and Lu^3＋ on the crystal structure and luminescence properties of （Yo96-x LnxCe0.04）3Al5O12（Ln = Gd, La, Lu） phosphors were studied. The X-ray diffraction patterns presented that with the inerease of the doping concentrations of La^3＋ and Gd^3＋ ions, the d-value of （Y0.96-xLnxCe0.04）3Al5O12 （Ln = Gd, La） inereased and the larger the doping ion, the stronger the effect would be. The doping amount causing phase transition in （Y0.96-xLnxCe0.04）3Al5O12 decreased with the inerease of the ionic radii of the doping lanthanide ions （La^3＋： 0.106 nm, Gd^3＋： 0. 094 nm, Lu^3＋ ： 0.083 nm）. The bigger doping ion of Gd^3＋ made the emission of （Y0.96-xGdxCe0.04）3Al5O12 move to red spectral region, but the smaller one of Lu^3＋ made it blue.     

Study on analysis of crystal structure in CeO₂ doped with Er₂O₃ or Gd₂O₃

To simulate the effects of burnable poison doping in nuclear fuel UO2,Er2O3(or Gd2O3)-doped CeO2 pellets were prepared. Changes in lattice constant and atomic disordering for CeO2 due to the Er2O3 and Gd2O3 doping were measured by means of XRD and XAFS. By the Er2O3 doping,the lattice constant decreased,and a disordering of lattice structure was induced in the samples. The doping with Er2O3 also induced the disordering of atomic arrangement around Er atoms,which was observed through the change in XAFS spectra. In contrast,the effect of Gd2O3 doping was smaller than that of Er2O3 doping. The result was discussed in terms of ionic size of dopants in CeO2 crystal.     

Effect of ytterbium inclusion in hafnium oxide on the structural and electrical properties of the high-k gate dielectric

Abstract： The undoped and Yb-doped HfO2 thin films were deposited on p-type single crystal St（100） substrates using RF magnetron sputtering method. The structure and electrical properties were investigated as a function of doping concentrations. The results showed that the presence of Yb could stabilize HfO2 in cubic phase. The dielectric constant was enhanced after in- troducing Yb3＋ ions into the HfO2 host. Compared with undoped HfO2 thin film, the Yb-doped l-IfO2 thin film exhibited a low leakage current. The silicate reaction between rare earth ions and SiO2 layers was used to eliminate interfacial silica and form a stable interface.     

Emission enhancement and color modulation of Tm(Ho)/Yb codoped Gd_2(MoO_4)_3 thin films via the use of multilayered structure

The multilayered structure thin films(Gd_2(MoO_4)_3:Ho(Tm)/Yb@Gd_2(MoO_4)_3:Yb)) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-conversion luminescence of Gd2(MoO_4)3:Ho(Tm)/Yb@Gd2(MoO_4)3:Yb thin films,The results show that the double-layer structured thin films are able to increase the emission intensity.The fluorescence enhancement factors of the luminescence from Gd2(MoO_4)3:Ho/Yb@Gd2(MoO_4)3:Yb thin films,located at540 and 662 nm,reach 7.5 and 4.3,respectively.And the enhancement factors of emissions located at450,475 and 650 nm(Gd_2(MoO_4)3:Tm/Yb@Gd_2(MoO_4)_3:Yb)) reach 9,2 and 2,respectively.The considerable enhancement is due to the suppression of surface quenching and energy harvesting via the Yb ions in the outer shell.In addition,the emission color of thin films can be modulated from yellow to blue via tuning the number of Gd2(MoO_4)3:Ho/Yb and Gd2(MoO_4)3:Tm/Yb layers,which provides a feasible strategy to tune the up-conversion emission color.     

Luminescence Properties of Tb^3＋ -Doped LuAG Films Prepared by Pechini Sol-Gel Method

Lu3Al5O12（LuAG） thin films with different Tb^3＋ concentration were prepared on carefully cleaned （111 ） silicon wafer by a Peehini process and dip-coating technique. Heat treatment was performed in the temperature range from 800 to 1100 ℃. The crystal structure was analyzed by XRD. The results show that LuAG film starts to crystallize at about 900 ℃, and the particle size increases with the sintering temperature. Excitation and emission spectra of Tb^3＋ doped LuAG films were measured. The effects of heat-treatment temperature and doping concentration of Th3 ＋ on the luminescent properties were also investigated. For a comparison study, Th^3＋-doped LuAG powders were also prepared by the same sol-gel method.     

A Study of Pb-Doping Effect on Structural,Optical, and Morphological Properties of ZnO Thin Films Deposited by Sol–Gel Spin Coating

In our study, undoped and lead (Pb)-doped ZnO thin films were deposited by sol–gel spin-coating technique and the structural, morphological, and optical properties of the films were investigated as a function of Pb doping which was changed from 0 to 4 at. pct with 1 at. pct step. The XRD results exhibited that the films had a hexagonal wurtzite structure with (002) preferential orientation in all dopant ratios. The grain size values of Pb-doped films were lower than that of undoped ZnO, but the increase in strain and dislocation density values were observed with Pb doping. Detailed optical analysis showed that the average transmittance of all films varied between about 90 and 99 pct and the absorption edge of undoped ZnO film shifted from longer wavelength to short wavelengths (blue shift) with Pb doping. The optical band gap and Urbach energy values of undoped ZnO increased from 3.283 eV and 63 meV to 3.331 eV and 88 meV with increasing Pb doping ratio. But steepness parameter values showed reversely variation with increasing Pb doping. The AFM images expressed that the films had homogenous nanoparticle distribution on the surface and particle size of ZnO decreased with Pb doping ratio. These results suggested that undoped and Pb-doped ZnO thin films could be used in many technological areas.     

Phase control of magnetron sputtering deposited Gd2O3 thin films as high-κ gate dielectrics

Gd2O3 thin films as high-κ gate dielectrics were deposited directly on Si(001) substrates by magnetron sputtering at a pressure of 1.3 Pa and different temperatures. X-ray diffraction results revealed that all the films grown from 450 to 570℃ were crystalline, and the Gd2O3 thin films consisted of a mixture of cubic and monoclinic phases. The growth temperature was a critical parameter for the phase constituents and their relative amount. Low temperature was favorable for the formation of cubic phase while higher temperature gave rise to more monoclinic phase. All the Gd2O3 thin films grown from different temperatures exhibited acceptable electrical properties, such as low leakage current density (JL) of 10-5 A/cm2 at zero bias with capacitance equivalent SiO2 thickness in the range of 6-13 nm. Through the comparison between films grown at 450 and 570℃, the existence of monoclinic phase caused an increase in JL by nearly one order of magnitude and a reduction of effective dielectric constant from 17 to 9.     

Improvement of Luminescent Properties of PbWO4 by Doping with Gd3＋ Ions

The luminescent properties of PbW04: Gd3 were studied. The luminescence of Gd3 in PbWO4: Gd3 was quenched. It is possible that the excitation states of Gd3 locate in the conduction band of PbW04 crystal. The luminescent intensity of the green and the blue band of PbW04 emission increases by doping with about 0.005% and 0.01% (molar fraction) Gd3 respectively. Mechanism of this enhancement of PbWO4:Gd3 luminescence is probably due to energy transfer from Gd3 to PbW04 host in the crystal. The PbW04 doped with low concentration of Gd (about 0.005% -0.01% ) is a good scintillating material.     

Epitaxy of silicon doped gallium arsenide by molecular beam method

The molecular beam method is a versatile experimental technique which may be used to grow high quality single crystal thin films in the range from 100Å to several microns with precise control of uniformity and thickness. Films may be doped by an additional molecular beam containing the doping material simultaneously impinging on the substrate surface with the film molecular beams. Epitaxial GaAs thin films doped with silicon were grown by the molecular beam method in an ultrahigh vacuum system in which high energy electron diffraction and mass spectrometric measurements could be made during growth or by stopping growth momentarily. The crystallinity and beam intensity parameters of these films were thus studied during growth. The doping profiles and the amount of compensation were evaluated by the Schottky barrier diode method and the photo luminescence spectra.