Bi1.65Zn1.0Nb1.5O7.225陶瓷和薄膜的结构和介电性能对比

以立方焦绿石Bi1.5Zn1.0Nb1.5O7(BZN)为配方基础,通过掺入过量10％的Bi2O3,形成Bi1.65Zn1.0Nb1.5O7.225非化学计量比分子式.采用固相反应法合成具有焦绿石立方结构的Bi1.65Zn1.0Nb1.5O7.225陶瓷,并采用脉冲激光沉积法在Pt/SiO2/Si(100)基片上制备其薄膜.对比研究了非化学计量比Bi1.5Zn1.0Nb1.5O7.225陶瓷和薄膜的结晶性能,微观形貌以及介电性能的差异.结果表明烧结的Bi1.65Zn1.0Nb1.5O7.225陶瓷和沉积的BZN薄膜都保持立方焦绿石单相结构,但是薄膜展现出较强的(222)晶面择优取向.陶瓷和薄膜的晶格常数,微观形貌都体现出差异.对比二者的介电特性后发现,Bi1.65Zn1.0Nb1.5O7.225薄膜的介电常数明显高于陶瓷的介电常数,这归因于薄膜和块体材料之间的差异,例如厚度,致密度,择优取向等.     

Mg掺杂对ZnO薄膜结构与磁性的影响

采用脉冲激光沉积(PLD)方法在单晶Si(100)衬底上制备Zn1-xMgxO薄膜,研究了退火温度和氧压对Zn1-xMgxO薄膜的结构和磁性的影响.结果表明,Mg掺入量影响ZnO结构相变,当x≥0.25时,Zn1-xMgxO薄膜由六角纤锌矿结构变为立方结构,同时磁性增强.随着氧压的增大和后续退火温度的升高,都会使饱和磁化强度(Ms)呈先增大后减小的趋势.分析表明磁性的变化都与样品中的表面缺陷浓度有关.     

磁控溅射气体参数对氧化铟薄膜特性的影响

采用射频磁控溅射法生长氧化铟薄膜,研究了溅射气压和溅射气体对氧化铟薄膜结构及光电特性的影响.X射线衍射结果表明制得的薄膜为立方结构的多晶体,随着溅射气压的升高,薄膜晶粒尺寸变大.1 Pa下沉积的氧化铟薄膜具有最大的迁移率和最小的载流子浓度,分别为15.2 cm2/V·s和1.19×1019cm-3.用O2溅射的氧化铟薄膜载流子浓度降至4.39×1013cm-3,在红外区(1.5～5.5μm)的平均透射率为85;,高于Ar溅射的薄膜,这可能是由于O2的加入减少了氧空位,降低了载流子浓度,使得自由载流子对红外光的吸收减弱.     

钠掺杂对Bi1.5ZnNb1.5O7陶瓷结构和介电弛豫的影响

采用二次固相反应法制备Bi1.5-xNaxZnNb1.5O7(BNZN,0相似文献   

不同氧压下脉冲激光沉积LiCoO2薄膜的研究

使用脉冲激光沉积(PLD)法,在不同的氧压下制备了锂离子二次电池正极材料LiCoO2的薄膜.利用X射线衍射(XRD)、原子力显微镜(AFM)等分析测试方法,对沉积的薄膜进行了晶体结构和表面形貌的分析.结果显示,氧压达到正常标准时(加Pa),LiCoO:薄膜具有明显的c轴择优取向,同时薄膜的晶粒尺寸更为均匀,表面更为光滑.而氧压较低(1 Pa)时,薄膜表现为随机取向.这些结果表明,PLD方法制备LiCoO2薄膜时应该充分考虑腔体气压对等离子体的散射作用以提高薄膜表面的质量.     

钙钛矿型氧化物电极对Ba0.6Sr0.4TiO3薄膜电学性能的影响

采用脉冲激光沉积技术(PLD)在单晶基片LaAlO3(001)、MgO(002)上分别制备Ba06Sr04TiO3/La0.5Sr05CoO3(BST/LSCO)、Ba0.6Sr04TiO3/SrRuO3 (BST/SRO)异质结构,研究了LSCO和SRO底电极对BST薄膜晶相结构、表面形貌及BST薄膜电容器的电学特性的影响.研究发现,沉积在钙钛矿氧化物底电极上的BST薄膜表面平整,并都具有良好的外延生长.由于生长在LSCO底电极BST薄膜的压应力大于生长在SRO底电极的压应力,BST/LSCO异质结构的介电可调率为79.58;,而BST/SRO的介电可调率仅为68.26;,两种底电极上生长的BST薄膜都具有较低的漏电流.     

晶格失配和退火氧压对La_(0.825)Ca_(0.175)MnO_3薄膜的电学性能的影响（英文）

采用紫外脉冲激光沉积技术分别在LaA lO 3(LAO)、(LaA lO 3)0.3-(SrA lT aO 6)0.7(LSAT)和SrT iO 3(STO)(001)单晶衬底上制备了La0.825Ca0.175MnO 3(LCMO)薄膜。实验发现衬底的晶格失配度和退火氧压对薄膜结晶质量和电学性能有重要影响。电阻-温度曲线显示,生长在LAO(压应变)的LCMO薄膜比生长在STO(拉伸应变)的薄膜有更高的绝缘体-金属转变温度Tp和更大的电阻温度系数(TCR)。增加退火氧压可以有效地提高薄膜的Tp和TCR值。当退火氧压为30000 Pa时,与衬底晶格失配度最小的LCMO/LSAT薄膜具有最高的Tp(234.5 K)和最大的TCR(22.4%)。实验结果表明Ca含量为0.175的La1-xCaxMnO 3薄膜材料在测辐射热计等方面有潜在的应用前景。     

Ag掺杂ZnO薄膜结构和光学特性研究

采用脉冲激光沉积技术制备出了Ag掺杂的ZnO薄膜.研究了Ag含量、衬底温度及氧压对ZnO结构和光学性能的影响.结果表明:Ag以替位形式存在于ZnO晶格中,Ag掺杂浓度较低时,样品具有高度c轴择优取向.衬底温度越高,薄膜的结晶质量越好,光学带隙越接近纯ZnO的带隙,而其紫外荧光峰在衬底温度为300 ℃时最强.氧压为10 Pa时,薄膜的结晶质量最好,紫外峰最强,其带隙则随氧压的增大呈先变窄后加宽的趋势.     

氮化钛/氧化锰复合薄膜制备及其SERS特性研究

以四氯化钛为钛源,采用氨气还原氮化法得到氮化钛薄膜,再以草酸锰为原料,通过电化学沉积法在氮化钛薄膜表面沉积氧化锰纳米结构,利用XRD、XPS、FE-SEM、RAMAN测试表征薄膜组成、结构及其表面增强拉曼光谱(SERS)性能.XPS分析表明制备的复合薄膜中Mn元素以多种价态形式存在,利用XRD对薄膜晶相分析发现氮化钛为面心立方晶型,氧化锰为无定形.随着沉积时间的增加,沉积在薄膜上的氧化锰颗粒长大,并逐渐细化呈细条状,薄膜表面变得粗糙.利用R6G作为拉曼探针分子研究氮化钛/氧化锰复合薄膜的SERS效应,结果表明,氮化钛/氧化锰复合薄膜具有拉曼增强效应,在沉积时间为30 s时达到最大值,拉曼信号强度是纯氮化钛薄膜的2倍,且复合薄膜均匀性较好,拉曼检测极限为10-5 mol·L-1,经计算其拉曼增强因子为7.412×102.由此可见,采用电化学沉积制备的氮化钛/氧化锰复合薄膜具有作为SERS基底材料的应用潜力.     

脉冲激光沉积法在SiO2/Si衬底上生长c轴取向LiTaO3薄膜

本文利用脉冲激光沉积法,系统研究了衬底温度和氧压对硅基LiTaO3薄膜质量及c轴取向性的影响,结果表明衬底温度和氧压对LiTaO3薄膜的c轴取向性及结晶质量有很大的影响,在650℃、30Pa时可以生长出高c轴取向LiTaO3薄膜。采用扫描电镜和原子力显微镜对最佳条件下制得薄膜的表面形貌进行了分析,发现薄膜表面光滑,晶粒尺寸均匀致密,薄膜表面粗糙度约为3.6nm。     

Crystalline and electrical properties of pulsed laser deposited BST on platinized silicon substrates

In order to produce thin film capacitors with elevated capacitance and breakdown strength, pulsed laser deposition of the ferroelectric material Ba_0.6Sr_0.4TiO₃ (BST) has been made on (1 1 1)Pt/Ti/SiO₂/Si substrates. The films are in situ crystallized at 700 °C, polycrystalline in nature, and exhibit a single perovskite phase. This paper reports on both the effect of the oxygen pressure during heating and deposition, and the influence of different modes of introduction during the deposition stage, on the crystalline and electrical properties of the BST films. Orientation of films depends on the deposition oxygen pressure, with a (1 1 1) preferential orientation obtained when depositing under vacuum. XRD characterization reveals that the out-of-plane parameter of BST films increases when depositions are made under lower oxygen pressure. This phenomenon is related to a higher concentration of vacancies and defects in the films grown under low-pressure environment. However, a local introduction of oxygen on the substrate improves the annihilation of these defects. The crystalline orientation of the films is also highly dependent on the residual oxygen pressure during heating. A high (1 1 1) preferentially oriented BST film is obtained when heating and depositing under 0.1 mbar oxygen pressure. The heating atmosphere is thought to influence the out-diffusion of titanium on the surface of the Pt layer, thus modifying the nucleation and growth of BST films. Aluminum electrodes have been deposited on top of the BST films by dc sputtering to measure electrical capacitances. The calculated dielectric constant of in situ crystallized films deposited under 0.1 mbar oxygen pressure exceeds 500 at 100 kHz under zero dc bias. This high dielectric constant value obtained without post-deposition treatment appears to be of great technological interest.     

Fabrication and characteristics of CeO2 films on Si(1 0 0) substrates by pulsed laser deposition

A detailed investigation about the dependence of film orientation on deposition temperature and ambient oxygen pressure has been carried out for CeO₂ films on Si(1 0 0) substrates using pulsed laser deposition. It has been found that the CeO₂ film orientation varies with increasing oxygen pressure at 750°C deposition temperature. In addition, the recovery of preferential orientation of CeO₂ films grown at 20 Pa ambient oxygen pressure with increasing deposition temperature has also been found for the first time. X-ray photoelectron spectroscopy (XPS) measurements confirm that stoichiometric CeO₂ films can be grown at lower oxygen pressure (5×10⁻³ Pa). HRTEM result also indicates that the CeO₂ films grown at low oxygen pressure are of high crystallinity.     

气相输运沉积制备c轴择优取向的碘化铋薄膜

铋基卤化物材料因其无毒和优良的光电性能而显示出巨大的应用潜力。BiI₃作为一种层状重金属半导体,已被用于X射线检测、γ射线检测和压力传感器等领域,最近其作为一种薄膜太阳能电池吸收材料备受关注。本文采用简单的气相输运沉积(VTD)法,以BiI₃晶体粉末作为蒸发源,在玻璃基底上得到高质量c轴择优取向的BiI₃薄膜。并通过研究蒸发源温度和沉积距离对薄膜物相和形貌的影响,分析了BiI₃薄膜择优生长的机理。结果表明VTD法制备的BiI₃薄膜属于三斜晶系,其光学带隙为~1.8 eV。沉积温度对薄膜的择优取向有较大影响,在沉积温度低于270 ℃时,沉积的薄膜具有沿c轴择优取向生长的特点,超过此温度,c轴择优取向生长消失。在衬底温度为250 ℃、沉积距离为15 cm时制备的薄膜结晶性能最好,晶体形貌为片状八面体。     

MgO(100)衬底上生长BaTi2O5薄膜及其性能研究

利用脉冲激光沉积技术,在MgO(100)衬底上生长了BaTi2O5薄膜,探讨了沉积条件(衬底温度和氧分压)对薄膜结构的影响,并对其介电和光学性能进行了研究.结果表明:随衬底温度和氧分压的改变,BaTi2O5薄膜的物相和结晶取向逐渐变化;适宜的脉冲激光沉积工艺为衬底温度950~1000 K、氧分压12.5 Pa,在该条件下获得了b轴方向择优生长的BaTi2O5薄膜;该薄膜具有较高的居里温度(750 K),介电常数达2000,而且在可见光和红外波长范围内具有较高的透过率.     

衬底温度对氧化锌薄膜微结构及光学性能的影响

衬底温度是磁控溅射法制备氧化锌薄膜中一个非常重要的工艺指标,探索衬底温度对氧化锌薄膜微结构及光学性能的影响对制备环保型高质量氧化锌紫外屏蔽材料具有重要意义。以质量分数99.99%的氧化锌陶瓷靶为溅射源,利用射频磁控溅射技术在石英衬底上沉积了氧化锌紫外屏蔽薄膜,通过X射线衍射仪、薄膜测厚仪、紫外-可见分光光度计、荧光分光光度计进行测试和表征,研究了不同衬底温度对ZnO薄膜微结构及光学性能的影响。实验结果表明:制备所得薄膜均为六角纤锌矿结构,具有沿(002)晶面择优取向生长的特点,其晶格常数、晶粒尺寸、透过率、光学能隙、可见荧光、结晶质量等都与衬底温度密切相关,当衬底温度为250 ℃,溅射功率160 W,氩气压强0.5 Pa,氩气流速8.3 mL/min,沉积时间60 min时,所得氧化锌薄膜样品取向性最好,晶粒尺寸最大,薄膜结构致密,具有良好的光学性能和结晶质量。     

Effect of Thermal Annealing on Structural Properties,Morphologies and Electrical Properties of TiO2 Thin Films Grown by MOCVD

TiO₂ thin films, were deposited on Si(100) and Si(111) substrates by metalorganic chemical vapor deposition at 500 °C, and have been annealed for 2 min, 30 min and 10 hours at the temperature from 600 °C to 900 °C, in oxygen and air flow, respectively. XRD and atomic force microscopy characterized the structural properties and surface morphologies of the films. As‐deposited films show anatase polycrystalline structure with a surface morphology of regular rectangled grains with distinct boundaries. Rutile phase formed for films annealed above 600 °C, and pure rutile polycrystalline films with (110) orientation can be obtained after annealing under adequate conditions. Rutile annealed films exhibit a surface morphology of equiaxed grains without distinct boundaries. The effects of substrate orientation, annealing time and atmosphere on the structure and surface morphology of films have also been studied. Capacitance‐Voltage measurements have been performed for films deposited on Si(100) before and after annealing. The dielectric properties of TiO₂ films were greatly improved by thermal annealing above 600 °C in oxygen.     

直流反应磁控溅射法制备ZnO: Zr透明导电薄膜

以Zn∶ Zr为靶材,利用直流反应磁控溅射法制备了ZnO∶ Zr透明导电薄薄膜.研究了沉积压强对ZnO∶ Zr薄膜形貌、结构、光学及电学性能的影响.实验结果表明所制备的ZnO∶ Zr为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向.沉积压强对ZnO∶ Zr薄膜的晶化程度、形貌、生长速率和电阻率影响很大,而对其光学性能如透光率、光学带隙及折射率影响不大.当沉积压强为2Pa时,ZnO∶ Zr薄膜的电阻率达到最小值2.0×10-3Ω ·cm,其可见光平均透过率和平均折射率分别为83.2％和1.97.     

Epitaxial growth of ZnO thin films on Si substrates by PLD technique

Epitaxial ZnO thin films have been grown on Si(1 1 1) substrates at temperatures between 550 and 700 °C with an oxygen pressure of 60 Pa by pulsed laser deposition (PLD). A ZnO thin film deposited at 500 °C in no-oxygen ambient was used as a buffer layer for the ZnO growth. In situ reflection high-energy electron diffraction (RHEED) observations show that ZnO thin films directly deposited on Si are of a polycrystalline structure, and the crystallinity is deteriorated with an increase of substrate temperature as reflected by the evolution of RHEED patterns from the mixture of spots and rings to single rings. In contrast, the ZnO films grown on a homo-buffer layer exhibit aligned spotty patterns indicating an epitaxial growth. Among the ZnO thin films with a buffer layer, the film grown at 650 °C shows the best structural quality and the strongest ultraviolet (UV) emission with a full-width at half-maximum (FWHM) of 86 meV. It is found that the ZnO film with a buffer layer has better crystallinity than the film without the buffer layer at the same substrate temperature, while the film without the buffer layer shows a more intense UV emission. Possible reasons and preventive methods are suggested to obtain highly optical quality films.     

Structure of Polycrystalline Cu Films as Solar Selective Coatings

Copper thin films (5–150 nm) were prepared by vacuum deposition with different rates (0.7, 1.5 and 3 nm/s). The position, intensity and profile of X-ray diffraction lines were analysed to study the phases, the crystallographic preferred orientation as well as the residual strain and crystallite size. The fcc polycrystalline Cu phase was revealed and no oxide phases were identified. The films were highly oriented with 〈111〉 fiber texture. The ratio of P₁₁₁/P₂₀₀ increased with the film thickness. Thus, in case of amorphous substrate, the type of the crystallographic texture of a film depends mainly on the structure of the deposited material. The crystallite size increases while the residual strain decreases, as the film thickness or the deposition rate is increased. The crystallite size was very small compared with the film thickness. The effect of deposition rate was pronounced specially from 0.7 to 1.5 nm/s.