纳米Al夹层Ga_2O_3深紫外透明导电膜的研究

用磁控溅射法在室温条件下制备了Al膜、Ga2O3膜及Ga2O3/Al/Ga2O3三层膜,对其光学和电学性能进行了表征。单层Al膜厚度大于7nm时,光学透射率在近紫外光区域大于可见光区域;Ga2O3膜在深紫外光区域(<300nm)透明,光学带隙4.96eV;Ga2O3/Al/Ga2O3三层膜透射率截止波长在245nm左右,随着顶层Ga2O3厚度增加,电导率减小,紫外光透射率峰位、吸收边、截止波长红移,透射率峰值先稍微增加,然后逐渐降低。顶层Ga2O3厚度为34nm时,Ga2O3/Al/Ga2O3三层膜在275nm处的透射率达70%,电导率为3346S.cm–1。     

室温下制备的ZnO/Ag/ZnO多层膜的性能

采用射频磁控溅射ZnO陶瓷靶、直流磁控溅射Ag靶的方法在室温下制备了不同厚度的ZnO/Ag/ZnO多层膜。对样品进行了研究。结果表明:随着Ag层厚度的增加,ZnO(002)衍射峰的强度先增加后减小,Ag(111)衍射峰的强度增强,ZnO/Ag/ZnO多层膜的面电阻先减小后趋于稳定。ZnO膜厚度增加,Ag膜易形成晶状结构,ZnO/Ag/ZnO多层膜的透射峰向长波方向移动。ZnO(60nm)/Ag(11nm)/ZnO(60nm)膜在554nm处的透过率高达92.3%,面电阻为4.2?/□,品质常数?TC最佳,约40×10–3/?。     

Ag层的厚度对ZnO/Ag/ZnO多层膜性能的影响

采用射频磁控溅射ZnO陶瓷靶、直流磁控溅射Ag靶的方法制备了不同厚度Ag夹层的ZnO(60nm)/Ag/ZnO(60nm)多层膜.分别用X射线衍射仪、紫外可见分光光度计、四探针测试仪对样品的结构、光学性质、电学性质进行了研究.结果表明:随着Ag层厚度的增加,ZnO/Ag/ZnO多层膜呈现多晶结构,Ag(111)衍射峰的强度增强.Ag夹层厚度为11nm时,ZnO(60nm)/Ag/ZnO(60nm)膜在554nm处的透过率高达92.3%.随着Ag层厚度的增加,Ag膜的特征吸收峰呈现红移和宽化,ZnO/Ag/ZnO多层膜的面电阻先减小后趋于稳定.     

Ag层的厚度对ZnO/Ag/ZnO多层膜性能的影响

采用射频磁控溅射ZnO陶瓷靶、直流磁控溅射Ag靶的方法制备了不同厚度Ag夹层的ZnO(60nm)/Ag/ZnO(60nm)多层膜.分别用X射线衍射仪、紫外可见分光光度计、四探针测试仪对样品的结构、光学性质、电学性质进行了研究.结果表明:随着Ag层厚度的增加,ZnO/Ag/ZnO多层膜呈现多晶结构,Ag(111)衍射峰的强度增强.Ag夹层厚度为11nm时,ZnO(60nm)/Ag/ZnO(60nm)膜在554nm处的透过率高达92.3%.随着Ag层厚度的增加,Ag膜的特征吸收峰呈现红移和宽化,ZnO/Ag/ZnO多层膜的面电阻先减小后趋于稳定.     

三氧化钼修饰银透明电极的光电性能及其应用研究

银(silver,Ag)纳米薄膜具有优异的导电性、延 展性、易制备等优点,是极具潜力的柔性透明电极材 料。通过真空热蒸镀制备不同厚度的银薄膜(6 nm、10 nm、14 nm、18 nm、20 nm、24 nm),由于光散射和 光吸收的共同作用, 其透过率随厚度的增加呈先减小、再增加、再减小的趋势,厚度为18 nm时最优,最高透过率约60%; 而面电阻则随厚度的增加逐渐减小。为提升银膜的透过率,引入高折射率(2.1)电介质三氧化钼(m olybdenum trioxide,MoO₃)对银膜进行修饰,制备了MoO₃/Ag/MoO₃(MAM)多层膜。结 果表明:引入MoO₃可以平滑 银膜表面,降低面电阻,并改善电导率;更重要的是“MoO₃/Ag”界面处会发生折射率耦合 ,大大提升多 层膜的整体透过率,透过率普遍增加至少10%。当银层的厚度为14 nm时,MAM多层膜的透过率最优, 可接近70%。最后,以银作为透明阴极,成功制备了双侧发光的绿光 有机发光二极管(organic light-emitting diode,OLED)。     

新型红光LED中ITO的特性研究

用真空电子束蒸镀的方法制备半导体发光二极管LED 所用的ITO(indium tin oxide)膜。利用TLM(transmission line model)研究ITO与GaP接触特性。在氮气环境,435℃条件下,快速热退火40s能获得最小的接触电阻4.3×10-3Ωcm2。Hall测试和俄偈电子能谱表明,影响接触电阻的主要原因是ITO载流子浓度的改变和In,Ga,O的扩散。另外,制作了以300nm ITO为窗口层的新型AlGaInP红光LED并研究其可靠性。发现ITO的退化导致了LED的电压持续升高。而ITO与GaP热膨胀系数的不同导致了LED的最终失效。     

衬底温度对ITO/Ga2O3深紫外透明导电薄膜性能的影响

用磁控溅射的方法在石英玻璃上制备了ITO/Ga₂O₃双层膜。用X射线衍射仪、扫描电镜、双光束分光光度计和霍尔效应测试仪研究了衬底温度对ITO/Ga₂O₃双层膜的结构、表面形貌、光学性能和电学性能的影响。双层膜结构受衬底温度的影响,当衬底温度从100C 升高到 350C时,薄膜的电阻率由6.71′10^-3 Ω.cm 降到 1.91′10^-3 Ω.cm。衬底温度300C制备的ITO(22nm)/Ga₂O₃(50nm)双层膜的面电阻为373.3Ω,在300nm波长的深紫外透过率为78.97%。     

ITO薄膜的电阻并联效应研究

采用电子束蒸发镀膜方法在K9玻璃基底上分别镀制了ITO/SiO₂/ITO,ITO/Ti₂O₃/ITO和ITO/MgF₂/ITO结构的多层薄膜,用四探针方块电阻仪测量薄膜表面的方块电阻,用原子力显微镜观测样品的表面微观形貌。结果显示,当ITO薄膜的粗糙度较大且介质薄膜的物理厚度小于100nm时,各层ITO薄膜之间通过山峰状的凸起结构相连通,导致样片表面的方块电阻测量值与各层ITO薄膜电阻的并联值相当。这表明,当ITO薄膜的粗糙度较大且介质薄膜厚度较小时,各层ITO薄膜表现出电阻并联效应。利用多层ITO薄膜的电阻并联效应设计并制备了450～1200nm超宽光谱透明导电薄膜,用四探针方块电阻仪测量了试验样片的表面方块电阻,用紫外-可见-近红外分光光度计测试了样片的光谱透射率。结果显示,在相同表面方块电阻条件下,相比于单层ITO薄膜,利用ITO薄膜电阻并联效应所制备的多层透明导电薄膜具有更高的光谱透射率。     

多金属层诱导透射紫外“日盲”探测成像滤光片设计与低温制备研究

基于SiO2/Al/SiO2三层夹层结构,结合使用多角度椭圆偏振谱和透射光谱精确反演获得了薄金属Al层光学常数,并研究分析了Al光学常数随膜层厚度的变化;在此基础上采用导纳匹配法,理论优化获得了三腔金属诱导透射紫外滤光膜,并系统分析了Al和SiO2介质匹配层制备误差对紫外滤光膜光谱性能的影响;进一步采用低温、高真空Al、SiO2薄膜生长工艺,成功获得了峰值波长位于218 nm附近,峰值透过率~23.1%,带宽~32 nm,在280 nm、318 nm波段的透过率分别约为0.5%和0.04%,400～700 nm、800~1 100 nm波段的截止度分别可达~5.0 OD、~4.5 OD的高性能三腔诱导透射紫外滤光片样品。相关研究结果对于高性能多腔诱导透射日盲紫外滤光片的设计与制备具有很好的指导意义。     

MoO3对有机太阳能电池性能影响的研究

采用MoO3作为阳极缓冲层,制备了结构为ITO/MoO3/P3HT/C60/Bphen/Ag的有机太阳能电池器件,研究了MoO3薄膜厚度对器件性能的影响。采用常用的等效电路模型,仿真计算得到MoO3缓冲层对器件串联电阻的影响。此外,测试了器件的吸收光谱,研究了MoO3缓冲层对器件光子吸收的作用。结果表明,在MoO3厚度为1 nm时,器件的短路电流密度、开路电压和填充因子都得到了提高。MoO3可以改善电极和有机层的界面接触性能,能够有效降低器件的串联电阻,提高载流子的传输和收集效率;同时,MoO3缓冲层透过率高,不会对器件的光吸收效率造成影响。     

氧化钌/氧化锰复合电极材料的性能研究

采用溶胶-凝胶法和水热合成反应法分别制备了氧化钌和氧化锰电极材料。进而采用胶体法制备了不同配比的氧化钌/氧化锰复合电极材料。利用扫描电镜和X射线衍射仪分别对电极材料的形貌及其结构进行表征。通过循环伏安法、恒流充放电、交流阻抗谱对复合电极进行电化学性能测试。结果表明：在氧化钌中加入适量的氧化锰的有助于降低氧化钌的成本和提高氧化钌的阻抗特性,当氧化锰的含量为60wt%时,在38%的H2SO4溶液中,扫描速度为20mV/s时,复合电极的比电容为438F/g,内阻为0.304Ω,且在经过300次循环充放电后,比容量仍保持92.5%,可作为较理想的超级电容器电极材料。     

Towards metal electrode interface scavenging of rare-earth scandates: A Sc2O3 and Gd2O3 study

Amorphous Gd₂O₃ and Sc₂O₃ thin films were deposited on Si by high-pressure sputtering (HPS). In order to reduce the uncontrolled interfacial SiO_x growth, firstly a metallic film of Gd or Sc was sputtered in pure Ar plasma. Subsequently, they were in situ plasma oxidized in an Ar/O₂ atmosphere. For post-processing interfacial SiO_x thickness reduction, three different top metal electrodes were studied: platinum, aluminum and titanium. For both dielectrics, it was found that Pt did not react with the films, while Al reacted with them forming an aluminate-like interface and, finally, Ti was effective in scavenging the SiO₂ interface thickness without severely compromising gate dielectric leakage.     

Bi离子掺杂GeO2-Nb2O5-X玻璃的近红外宽带发光特性研究

用高温熔融法,制备了Bi离子掺杂浓度为1mol%的80GeO2-10Nb2O5-10X(X=Li2O,Na2O,CaO)系列玻璃。分别测定了样品的差热分析(DTA)曲线、吸收光谱、发射光谱、荧光寿命及傅立叶红外光谱(FTIR)。从DTA曲线估算出样品的结晶起始温度和软化温度的差值达200℃以上,该玻璃系统具有良好的热稳定性。在吸收光谱中,观察到由Bi掺杂所引起的约511nm和722nm两处吸收峰。在808nm波长的激光二极管(LD)激发下,观察到发光中心约为1 300nm、荧光半高宽(FWHM)约为200nm、荧光寿命约为133μs的宽带发光。在3组分玻璃中,含Li2O的玻璃具有最强的近红外宽带发光。从其红外吸收光谱可推断Bi3+与Bi5+共存于玻璃中,玻璃的近红外宽带发光可能起因于Bi5+。     

Role of N2 during chemical dry etching of silicon oxide layers using NF3/N2/Ar remote plasmas

In this work, the role of N₂ gas during the chemical dry etching of silicon oxide layers in NF₃/N₂/Ar remote plasmas was investigated by analyzing the species in the plasma, the reaction by-products in the exhaust, and the chemical properties of the etched surface. Increasing the N₂ gas flow rate resulted in an initial increase in the oxide etch rate up to a maximum value, followed by a subsequent decrease. The increased etch rate of the silicon oxide layers was not ascribed to the increased surface arrival rate of fluorine, but to the enhanced oxygen removal from the silicon oxide caused by the formation of NO₂ molecules. Presumably, the NO radicals formed from the added N₂ gas react chemically with the oxygen in the oxide, leading to the breaking of the Si-O bonds and the effective removal of oxygen, which in turn enhances the formation of SiF₄ resulting in an increased etch rate.     

紫外─远红外宽波段NiMn2O4及Mn1.56Co0.96Ni0.48O4光学性质的研究

Mn-Co-Ni-O作为一种重要的热探测材料被广泛应用于各类领域。作者使用研磨和烧结的方法制备了NiMn2O4和Mn1.56Co0.96Ni0.48O4块体材料。通过X射线衍射实验研究了两种块体的结晶情况,发现半径较大的Co阳离子的加入会导致块体结晶性变差。通过椭圆偏振光谱测试分别获得了NiMn2O4和Mn1.56Co0.96Ni0.48O4在紫外-远红外宽波段的光学常数和介电常数,发现添加离子后二者光学性质(光学常数的强度和峰位)具有一定区别。利用傅里叶光谱仪得到了两种材料的反射光谱,并与用光学常数计算出的数值进行了比较,最后评估了表面粗糙度对反射谱的影响。     

Characterization of the annealing impact on La2O3/HfO2 and HfO2/La2O3 stacks for MOS applications

The impact of various rapid thermal annealing used during the integration on the La₂O₃/HfO₂ and HfO₂/La₂O₃ stacks deposited by Atomic Layer deposition was analyzed. The consequences of lanthanum localization in such stacks on the evolution of the films during the rapid thermal annealing are investigated in term of morphology, crystalline structure, silicate formation and film homogeneity as a function of the depth. It appeared that the La₂O₃ location has an impact on the temperature of the quadratic phase formation which could be linked to the formation of SiOHfLa silicate and the resistance of the films to dissolution in HF 0.05 wt%.     

Solvothermal synthesis of Bi2O3/BiVO4 heterojunction with enhanced visible-light photocatalytic performances

Novel, three-dimensional, flower-like Bi2O3/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solution of NaOH etching process. The as-obtained samples were fully characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Brunauer-Emmett-Teller surface area, and UV-vis diffusereflectance spectroscopy in detail. The crystallinity, microstructure, specific surface area, optical property and photocatalytic activity of samples greatly changed depending on solvothermal reaction time. The photocatalytic activities of samples were evaluated on the degradation of methyl orange (MO) under visible-light irradiation. The Bi2O3/BiVO4 exhibited much higher photocatalytic activities than pure BiVO4 and conventional TiO2 (P25). The result revealed that the three-dimensional heterojunction played a critical role in the separation of the electron and hole pairs and enhancement of the interfacial charge transfer efficiency, which was responsible for the enhanced photocatalytic activity.     

V2O4-PEPC composite based pressure sensor

In this study, V₂O₄-PEPC based pressure sensor was designed and fabricated by drop-casting the blend of V₂O₄-PEPC microcomposite thin films of vanadium oxide (V₂O₄) micropowder (10 wt.%) and poly-N-epoxypropylcarbazole, PEPC (2 wt.%) in benzol (1 ml) on steel substrates. The thickness of the V₂O₄-PEPC films was in the range of 20-40 μm. The DC resistance of the sensor was decreased in average by 24 times as the pressure was increased up to 11.7 kNm⁻². The resistance-pressure relationships were simulated.     

Electronic structure and magnetic properties of Ca3Co2O6 cobaltites: Intrachain magnetic ordering

The present study is focussed on the intrachain magnetic interactions between the trigonal prismatic (TP) and octahedral (OCT) Co sites in Ca₃Co₂O₆ cobaltites from their electronic structure determined using the first principle full potential linearized augmented plane wave method within the GGA+U approximation. The occurence of various magnetic solutions as a function of the Coulomb integral U of the GGA+U approach is investigated. Various magnetic configurations, corresponding to different total magnetization, are found only when the insulating state is reached for U > 2.5 eV and the most stable solution corresponds to a magnetic spin moment on the TP (respectively OCT) site around 2.6 (respectively 1) Bohr magneton.     

Low-pressure H2/N2 annealing on indium tin oxide film

Annealing of indium tin oxide (ITO) film in low-pressure H₂/N₂ was investigated. On carefully selecting the annealing process window, apparent electrical property improvement as well as good optical property can be obtained. It was found that ITO annealed with 2 Pa, H₂/N₂:6/6 sccm, at 500 °C for an hour can increase its electrical conductivity 60% more than ITO without annealing, 58% more than ITO annealed with pure H₂. An annealed ITO without specially selected recipe can easily possess worse electrical and optical properties than that without annealing. It can be explained that annealing ITO in a hydrogen-contained environment can lead to hydrogen reduction–oxygen vacancy playing a donor role in ITO; however, annealing also provides the energy to remove ITO material defects including donors.