退火温度对NiZn铁氧体薄膜性能的影响

用溶胶-凝胶(Sol-Gel)法在Si(100)基片上沉积了NiZn铁氧体薄膜,研究了退火温度对薄膜结构和磁性能的影响.XRD研究表明,薄膜具有立方尖晶石结构,但当退火温度为900 ℃时,有SiO2相出现,发生了明显的Si扩散.原子力显微镜(AFM)究表明,退火温度升高,薄膜晶粒尺寸逐渐变大,粗糙度相应增加.随着退火温度的升高,薄膜的饱和磁化强度(Ms)呈先增加后降低的趋势,而矫顽力(Hc)与Ms变化相反.当退火温度为700 ℃时,薄膜具有最优磁性能,Ms=360×103 A/m,Hc=6 764 A/m.     

还原温度对纳米FeCo/Al2O3复合薄膜结构和磁性的影响

采用溶胶-凝胶旋涂法和H2还原工艺制备了纳米FeCo/Al2O3复合薄膜.利用X射线衍射仪、扫描电子显微镜、原子力显微镜及振动样品磁强计研究了还原温度对薄膜结构、表面形貌和磁性的影响.结果表明,随着还原温度的升高,薄膜中FeCo的晶粒尺寸和晶格常数变大,薄膜的饱和磁化强度(Ms)也同时增大,其矫顽力(Hc)则先增大,后...     

Y和Cr共掺杂BiFeO_3陶瓷的多铁性能研究

采用固相反应法制备了Y_2O_3和Cr_2O_3共掺杂BiFeO3陶瓷,研究了Bi_(0.9)Y_(0.1)Fe_(1–x)Cr_xO_3(BYFC_x,x=0,0.002,0.004,0.006,0.008)陶瓷的多铁性能。XRD分析表明,经850℃烧结的BYFC_x陶瓷形成了三方钙钛矿结构固溶体。随着Cr掺杂量增加,BYFC_x陶瓷在室温下的铁磁性能和铁电性能提高明显。当x为0.004时,所制陶瓷的铁磁性能最好,剩余磁化强度Mr为0.23A·m~2/kg,饱和磁化强度Ms为3.15A·m~2/kg,矫顽力Hc为2.3kA/m。Mr、Ms和Hc随着Cr掺杂量的增加先增大后减小。     

氮化铝薄膜的厚度对场发射特性的影响

采用射频磁控溅射方法,在n型(100)Si基底上沉积了不同厚度(20~150 nm)纤锌矿结构的纳米AlN薄膜。在超高真空系统中测量了不同膜厚样品的场发射特性,发现阈值电场随着厚度的增加有增大的趋势。厚度为44 nm的AlN薄膜样品具有最低的阈值电场(10 V/μm),当外加电场为35 V/μm时,最高发射电流密度为284μA/cm2。AlN薄膜场发射F-N曲线表明,在外加电场作用下,电子隧穿了AlN薄膜表面势垒发射到真空。     

CoFe_2O_4纳米颗粒的共沉淀法制备及其磁性能

采用共沉淀法制备了CoFe2O4纳米颗粒,运用XRD、TEM和VSM测试手段,研究了煅烧温度对CoFe2O4的结构、形貌以及磁性能的影响。结果表明:CoFe2O4纳米颗粒的粒径大小均匀;煅烧前与经200℃和600℃煅烧的CoFe2O4纳米颗粒晶粒度分别约为15,20和30nm;CoFe2O4纳米颗粒的粒径、Ms、Mr和Hc随着煅烧温度的升高而增大。当煅烧温度为600℃时,Ms约为67A·m2·kg–1,Hc为4.67×107A·m–1。     

0.7BiFeO_3-0.3PbTiO_3薄膜结构与电学性能的厚度效应

以溶胶–凝胶法在Pt/Ti/SiO2/Si(111)基底上制备了厚度为30~1 110 nm的0.7BiFeO3-0.3PbTiO3(0.7BFO-0.3PT)薄膜,研究了薄膜厚度对0.7BFO-0.3PT薄膜的结构与电学性能的影响。结果表明,随着膜厚的增加,晶格常数c与a的比值c/a以及晶粒尺寸都呈现先增大后减小的趋势,但其剩余极化强度及介电常数却均与薄膜厚度呈正比。厚度为180 nm的0.7BFO-0.3PT薄膜具有最大的矫顽场(2.99×105V/cm)和晶粒均匀度(42 nm),同时其晶格常数比c/a也达到最大,为1.129 9。     

废旧锌锰电池制备Cu掺杂Mn-Zn铁氧体

以硝酸溶解废旧碱性锌锰电池所得的溶液为原料,以酒石酸为凝胶剂,采用sol-gel法制备出一系列Cu掺杂Mn-Zn铁氧体(Mn0.6–x/2Zn0.4–x/2CuxFe2O4,x=0.1,0.2,0.3和0.4)。经XRD、VSM测试,结果表明:Cu掺杂不仅没有改变Mn-Zn铁氧体的相结构,而且有利于尖晶石结构的形成;Cu掺杂后Mn-Zn铁氧体的Ms、Mr和Hc的变化趋势,都是先增大后减小,最适宜的掺杂量x为0.1。此时,Ms为2.66×105A/m,Mr为5.73×104A/m,Hc为1.6/π×104A/m。     

Al-N共掺杂ZnO:Mn稀磁半导体薄膜的结构与性能

采用反应磁控溅射法在室温下沉积前驱体氮化物,在大气环境、500℃下氧化退火30min后获得了Al-N共掺杂ZnO:Mn薄膜。研究了直流与射频反应磁控溅射对氧化退火薄膜结构和性能的影响。结果表明:两种工艺制备的退火薄膜均具有ZnO纤锌矿结构,且均为n型导电。射频溅射退火样品具有很好的c-轴择优取向,其表面光滑平整,表面粗糙度RMS值为1.2nm,且具有室温铁磁性,饱和磁化强度(Ms)和矫顽力(Hc)分别为46.8A·m–1和4.9×103A·m–1;而直流溅射退火样品表面凹凸不平,RMS值为25.8nm,室温下是反铁磁性的。     

聚合物复合薄膜DR13/PMMA的制备及其光学特性

薄膜的厚度、折射率和传输损耗等参数在电光系数的确定和光波导器件的设计和制作过程中都是重要的参考数据。采用旋涂法制备了三种不同质量比的偶氮化合物染料分散红13(DR13)与聚合物聚甲基丙烯酸甲酯(PMMA)复合薄膜;利用分光光度计测量样品的吸收光谱;利用棱镜耦合仪测量了薄膜的厚度和折射率,并对不同波长下的折射率进行拟合得到折射率色散曲线;采用视频摄像技术研究样品的光传输特性,利用自己编写的计算机程序来处理其实验结果。DR13/PMMA复合薄膜在300nm和500nm处有两个大的吸收峰,而在其他波段,尤其是在通信波段没有明显吸收。薄膜的膜厚大约为1~2μm,其折射率随着质量比的增加而增大,随着激光波长的增大而降低,膜厚和折射率的误差分别为3.2×10-1μm和1.5×10-3。三种质量比(10%,15%和20%)的薄膜传输损耗分别为1.5269dB/cm,2.7601dB/cm和3.6291dB/cm,可以看出随着DR13质量比的增大,光传输损耗也逐渐增大,即DR13的含量对于传输损耗的影响较大。     

利用MFM研究薄膜厚度对Co60Fe20B20薄膜磁畴结构的影响

本文利用磁力显微镜(MFM)主要研究了由磁控溅射法制备的Co60Fe20B20软磁薄膜的厚度变化(2.5nm～400nm)对薄膜磁畴结构的影响.在室温下观察到垂直各向异性随薄膜厚度的增大而增大.从薄膜的表面形貌像观察到在溅射过程中薄膜温度随薄膜厚度增大而升高.当薄膜厚度小于20nm时,磁畴尺寸随薄膜厚度的增大而增大;当薄膜厚度大于20nm时,磁畴尺寸随薄膜厚度的增大而减小;厚度在20nm附近时,畴壁尺寸达到一个最小值.     

不同厚度PZT薄膜的制备及电性能特性研究

采用sol-gel（溶胶-凝胶）法在Pt/Ti/SiO2/Si基底上分别制备了厚度为400nm,600nm,800nm的PZT（锆钛酸铅,Zr/Ti=52/48）薄膜,研究了厚度对薄膜介电性能与铁电性能的影响。通过对薄膜的铁电性能与介电性能进行测试,分析了不同厚度薄膜的剩余极化强度、介电常数与介电损耗;通过对介电调谐率与最大正切损耗的计算,进一步分析了薄膜的介电调谐性能。实验结果表明,薄膜的介电常数与介电损耗随薄膜厚度的增大而增加;厚度为600nm的薄膜具有最好的介电调谐性能与铁电性能。     

不同沉积方式SiO2薄膜的自然时效特性

SiO2薄膜是光学薄膜领域内常用的重要低折射率材料之一。文中采用不同沉积技术在Si基底上制备了SiO2薄膜,并研究了它们光学特性的自然时效特性。采用不同贮存时间的椭偏光谱表征SiO2薄膜的光学特性,随着时间的增加,EB-SiO2薄膜和IAD-SiO2薄膜的物理厚度和光学厚度随着增加,但IBS-SiO2薄膜随着减小,变化率分别为1.0%,2.3%和-0.2%。当贮存时间达到120天时,IBS-SiO2薄膜、EB-SiO2薄膜和IAD-SiO2薄膜的物理厚度和光学厚度趋于稳定。实验结果表明,IBS-SiO2薄膜的光学特性稳定性最好,在最外层保护薄膜选择中,应尽可能选择离子束溅射技术沉积SiO2薄膜。     

溶液PH值对CdS薄膜结构特性的影响

采用化学水浴沉积(CBD)工艺在玻璃衬底上制 备CdS薄膜,研究溶液PH值对CdS 薄膜结构特性的影响。薄膜的厚度、组份、晶相结构和表观形貌分别由台阶仪、X射线荧光 光谱(XRF)、X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)来表征。溶液的 PH值为11.26、 11.37和11.48时,CdS薄膜的晶相以六方相为主,薄膜的厚度先增大后减小; PH值为11.62、11.66时,薄膜的晶相以立方相为主,薄 膜的厚度进一步减小。同时,随着溶液PH值 增大,CdS薄膜的晶格常数也逐渐增大。两种晶相的CdS薄膜缓冲层与CIGS薄膜分别构成异 质 对形成异质结时的晶格失配分别为32.297%和1.419%,界面态密度分别为2.792×10¹⁴和8.507×10¹²,因此高效CIGS薄 膜太阳电池更需要立方相的CdS薄膜。     

磁控溅射不同厚度铝薄膜的微结构及其表面形貌

用直流磁控溅射法在室温的Si(100)基底上制备了21～55 nm范围内不同厚度的铝膜,并用X射线衍射和扫描电镜对薄膜的结构和表面形貌进行了表征.分析结果表明:制备的铝薄膜呈多晶状态,晶粒择优取向为(111),随着膜厚的增加,Al(100)衍射峰宽变窄,薄膜的平均晶粒尺寸逐渐增大,晶面间距逐渐减小,薄膜中的残余应力减小.膜厚为55 nm时,Al膜均匀致密.     

Preparation and Dielectric Characteristics of Semitransparent CoFe2O4–P(VDF-TrFE) Nanocomposite Films

Polymer–ceramic nanocomposites play an important role in embedded capacitors. However, polymer–ceramic dielectrics are limited for commercial applications due to their low transmittance, poor adhesion, and poor thermal stress reliability at high filler loadings. Thus, materials design and processing is critical to prepare films with improved dielectric properties and low filler loading. In this work, we use a spin coating-assisted method to fabricate poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)]–CoFe₂O₄ (CFO) nanocomposite films. Magnetic CFO nanoparticles in the size range of 10 nm to 40 nm were successfully synthesized using a hydrothermal process. The dispersion of the nanoparticles, the dielectric properties, and the transmittance of the nanocomposite films were studied. The dielectric constant of the nanocomposite films increased by about 45% over the frequency range of 100 Hz to 1 MHz, compared with that of pristine P(VDF-TrFE) film. Optical measurements indicated that the transmittance of the films remains above 60% in the visible range, indicating a relatively low content of CFO in the polymer matrix. Our experimental results suggest that spin coating-assisted dispersion may be a promising route to fabricate dielectric polymer–ceramic nanocomposite films of controllable thickness.     

Thickness Dependence Study of Electron Beam Evaporated LBMO Manganite Thin Films for Bolometer Applications

La_0.7Ba_0.3MnO₃ (LBMO) thin films with different thicknesses were deposited on Si substrates using an electron beam evaporation technique for bolometer applications. To evaluate the influence of the thickness on their structural, compositional, morphological, and electrical properties, the LBMO thin films were characterized by x-ray diffraction (XRD), energy-dispersive spectroscopy, atomic force microscopy, and a four-probe method. XRD measurements showed that the crystal quality of the LBMO films improved with increasing thickness. The surface morphology revealed that the grain size and surface roughness of the films increased with increasing thickness. The resistivity increased with increasing thickness of the film. The temperature coefficient of resistance of the LBMO films decreased from 5.15%/K to 4.12%/K with increase of the film thickness from 20 nm to 100 nm.     

ScAlN缓冲层厚度对Si(100)衬底上GaN外延层的影响

采用脉冲直流磁控溅射方法在Si(100)衬底上制备了ScAlN薄膜。以溅射的ScAlN作为缓冲层,在Si(100)衬底上用金属有机化学气相沉积(MOCVD)技术外延了GaN薄膜。使用高分辨X射线衍射、原子力显微镜和拉曼光谱研究了ScAlN缓冲层的厚度对ScAlN缓冲层和GaN外延层的影响。研究结果表明,ScAlN缓冲层的厚度是影响GaN薄膜晶体质量的重要因素。随着ScAlN厚度的增加,ScAlN的(002)面X射线衍射摇摆曲线半高宽持续减小,GaN的(002)面X射线衍射摇摆曲线半高宽先减小后增大。当ScAlN缓冲层厚度为500nm时,得到的GaN晶体质量最好,其中GaN(002)面的X射线衍射摇摆曲线半高宽为0.38°,由拉曼光谱计算得到的张应力为398.38MPa。     

Effect of bath temperature on the properties of CuInxGa1-x Se2 thin films grown by the electrodeposition technique

Electrodeposition is a promising and low cost method to synthesize CulnxGa1-xSe2 (CIGS)thin films as an absorber layer for solar cells. The effect of bath temperature on the properties of CIGS thin films was investigated in this paper. CIGS films of 1 μm thickness were electrodeposited potentiostatically from aqueous solution, containing trisodium citrate as a complexing agent, on Mo/glass substrate under a voltage of-0.75 V, and bath temperatures were varied from 20 to 60 ℃. The effects of bath temperature on the properties of CIGS thin films were characterized by X-ray diffraction (XRD) and scanning electron microscopy. XRD revealed the presence of the CuIn0.7Ga0.3Se2 phase, the optimal phase for application in solar cells. The grain dimensions and crystallizability increase along with the increase of the bath temperature, and the films become stacked and homogeneous. There were few changes in surface morphology and the composition of the films.     

退火温度对WO_3薄膜结构及气敏性能的影响

采用直流磁控溅射法制备了WO3薄膜,并在350~550℃时对薄膜进行退火处理,研究了退火温度对薄膜结构及气敏性能的影响。结果表明:退火前及350℃退火后的薄膜为非晶态,450℃和550℃退火后的薄膜为WO3–x型晶态;随退火温度的提高,薄膜厚度增加,晶粒度增大。550℃退火后薄膜的厚度,较450℃退火后薄膜厚30nm,晶粒度相差8nm;450℃和550℃退火后的薄膜,在150℃时对体积分数为0.05%的NO2的灵敏度接近于22。     

ZnSe/ITO thin films:candidate for CdTe solar cell window layer

The crystal structure, electrical and optical properties of ZnSe thin films deposited on an In₂O₃:Sn (ITO) substrate are evaluated for their suitability as the window layer of CdTe thin film solar cells. ZnSe thin films of 80, 90, and 100 nm thickness were deposited by a physical vapor deposition method on Indium tin oxide coated glass substrates. The lattice parameters are increased to 5.834 Å when the film thickness was 100 nm, which is close to that of CdS. The crystallite size is decreased with the increase of film thickness. The optical transmission analysis shows that the energy gap for the sample with the highest thickness has also increased and is very close to 2.7 eV. The photo decay is also studied as a function of ZnSe film thickness.