ZnO∶Sn/Ag/ZnO∶Sn复合薄膜电极的防氧化性能研究

随着分辨率的提高,传统金属电极在电阻率和抗氧化性能方面已经不适合作为需要高温热处理的场致发射显示器件中的薄膜电极.本文采用5.77%(原子比)Sn掺杂的ZnO∶Sn作为Ag层的保护层,利用磁控溅射法制备ZnO∶Sn/Ag/ZnO∶Sn复合薄膜及其电极,并采用X射线衍射、光学显微镜、扫描电子显微镜和电性能测试系统研究复合薄膜及其电极在经过不同温度退火后的晶体结构、表面形貌和电学性能的变化.ZnO∶Sn膜层致密,25 nm厚的ZnO∶Sn 足以保护Ag层在530℃的高温中不被明显氧化,电极电阻率低达2.0×10-8Ω·m左右.     

a-Si∶H/Al/a-Si∶H三层复合膜的低温晶化研究

采用真空热蒸发与PECVD方法 ,在特殊设计的“单反应室双沉积法”薄膜沉积设备中沉积a Si∶H/Al/a Si∶H三层复合薄膜 ,并利用XRD ,XPS及SEM等方法对薄膜在不同温度退火后的晶化行为进行了研究。结果表明 ,随着热处理过程的进行 ,金属Al逐步向表面扩散 ,在金属Al锈导下a Si∶H层出现晶化的温度不高于 2 5 0℃。在Al层厚度低于 2 2nm时 ,a Si∶H向晶态硅转变的量随着Al层厚度的增加而增加 ,而当Al层厚度大于 2 2nm后 ,a Si∶H向晶态硅转变的量与Al层厚度无关     

a-Si∶H/a-Ge∶H超晶格的界面特性研究

本文用红外(IR)和拉曼(Raman)谱研究了反应溅射 a-Si∶H/a-Ge∶H 超晶格的界面特性.定量分析发现,界面处没有因应力释放引起的 H 富集,不存在由超晶格结构引起的界面结构无序,界面处存在着～(5±2)(?)的 Si、Ge 组分混合层.我们对结果进行了初步分析.     

SrI2∶Eu∶Cs晶体生长及闪烁性能

采用垂直布里奇曼法成功制备出尺寸为Φ25 mm×70 mm的SrI₂∶Eu∶Cs晶体,经加工后封装得到尺寸为10 mm×10 mm×10 mm的透明单晶,这是迄今为止Eu²⁺和Cs⁺双掺杂的最大尺寸SrI₂单晶,所用原料为国产原料。XRD测试结果表明,所得晶体为SrI₂正交相,空间群为Pbca。荧光光谱显示晶体的发射峰和激发峰分别位于440 nm和419 nm,属于典型Eu²⁺的5d→4f跃迁发射。X射线激发发射光谱显示该晶体只有一个位于440 nm的发射峰,与荧光光谱的结果一致。采用单指数拟合后得到晶体在370 nm激发波长下的荧光寿命约为1.3 μs。在¹³⁷Cs射线源激发下的γ能谱测试显示晶体的能量分辨率为5.5%,已基本满足实际使用的要求。     

渐变组分a-Si∶H/a-SiC∶H膜内部电场的研究

本文报导了渐变组分 a-Si∶H/a-SiC∶H 膜的制备,研究了渐变膜的电学、光学特性,用 EHT 方法对 a-Si∶H 和 a-SiC∶H 的能态密度进行了计算。提出该渐变膜是一种连续变带隙材料,其内部存在自建电场,并从实验上确定了自建电场的方向。     

二极管近贴泵浦Nd∶YVO4/Cr∶YAG被动调Q激光器

报道了采用国产1W连续激光二极管近贴式泵浦Nd∶YVO4晶体,慢饱和吸收体Cr∶YAG 被动调Q结构的全固体、高效率、高稳定性、高重复频率1064nm红外激光器.在注入泵浦功率为600mW时,得到平均功率138mW、脉冲宽度19.8ns、重复频率170.1kHz、峰值功率40.96W的被动调Q红外激光输出.在平均功率100mW下连续运转1小时,测得脉冲峰值稳定性优于1.8%,周期稳定性优于2%.     

影响a-Si∶H/a-SiN_x∶H多层膜PPC效应的某些因素

本文由实验给出了曝光强度,多层膜的层数和内应力对 a-Si∶H/a-SiN_x∶H 多层膜持久光电导(PPC)效应的影响及结果分析。     

a-Si∶H/a-SiC∶H多层薄膜的光、电特性研究

采用射频等离子体增强化学气相沉积(PECVD)技术,以SiH_4、CH_4和H_2为反应气体,在单晶硅和石英衬底上制备a-Si∶H/a-SiC∶H多层薄膜。利用透射电子显微镜(TEM)对样品的微结构进行了表征,同时对其电子输运性质和光吸收特性进行了实验研究。结果表明,本实验条件下制备的多层薄膜样品为非晶态多层薄膜结构,并且样品具有良好的周期性结构和陡峭的界面特性。室温条件下,样品在垂直方向上呈现出多势垒顺序共振隧穿特性。由于量子限制效应,当a-Si∶H势阱层厚度8nm,随着势阱层厚度减小,样品的光学带隙增大,光吸收系数减小。     

a-SiNx∶H薄膜的导电机制

研究了a-SiN     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Synthesis of a new perovskite Pb(Li14Nb34)O3

A high-pressure technique was adopted to obtain perovskite-type $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$. A new perovskite $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$ was characterized to have a cubic symmetry with $\text{a}{}_{\mathrm{<mtext>o</mtext>}}\text{= 4.069}\text{A}\text{?}$; Li and Nb ions in the B-site of perovskite lattice may be in a random arrangement.     

Optimization of AlxOy/Pt/AlxOy multilayer spectrally selective coatings for solar-thermal applications

Spectrally selective Al_xO_y/Pt/Al_xO_y multilayer absorber coatings were deposited onto corning 1737 glass, Si (111) and copper substrates using electron beam (e-beam) vacuum evaporator at room temperature. The employment of ellipsometric measurements and optical simulation was proposed as an effective method to optimize and deposit multilayer solar absorber coatings. The optical constants (n and k) measured using spectroscopic ellipsometry, showed that both Al_xO_y layers, which used in the coatings, were dielectric in nature and the Pt layer was semi-transparent. The optimized multilayer coatings exhibited high solar absorptance α ∼ 0.94 ± 0.01 and low thermal emittance ? ∼ 0.06 ± 0.01 at 82 °C. The Rutherford backscattering spectroscopy (RBS) data of Al_xO_y/Pt/Al_xO_y multilayer absorber indicated the Al_xO_y layers present in the coating were nearly stoichiometry. The scanning electron microscope analysis (SEM) result indicated that the average diameter and inter-particles distance of Pt grains were statistically about 146 ± 0.17 nm and 6-10 ± 0.2 nm respectively.     

Bulk crystalline BaPb34Bi14O3: A ceramic superconductor

The preparation conditions of the high T_C ceramic superconductor Ba(Pb,Bi)O₃ is correlated with the superconducting transition. Transition onsets of all materials are similar, but transition widths and transition completeness is strongly dependent on firing temperature. Only materials prepared over a narrow temperature range, resulting in a nearly ideal weight loss, have a complete and narrow transition.     

Electrostriction in Pb (Zn13Nb23)O3

The electrostriction in $\text{Pb (Zn}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{Nb}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{)}\text{O}{}_3$ crystals has been investigated using a strain gauge method. In the ferroelectric phase below 140 C, the strain vs the electric field shows a hysteresis, which is ascribed to the effect of ferroelectric domains. A quadratic relation holds between the strain x and the electric polarization P as x = QP² above about 170 C in the paraelectric phase. Values of the electrostrictive Q coefficients are determined from the measurements near 190 C, as Q₁₁ = 1.6·10^?2m⁴/C², Q₁₂ = ?0.86·10^?2m⁴/C², and Q₄₄ = 0.85·10^?2m⁴/C².     

Magnetic,electrical and thermal studies on the V1−xMox02

The monoclinic-to-tetragonal structure transition of oxides V_1?xMo_x0₂ with $\text{0≤}\text{x}\text{≤0.20}$ has been studied by means of DTA, X-ray diffraction, magnetic susceptibility (powder samples) and electrical conductivity (single crystals) measurements within the temperature region 80 K to 400 K. A linear decrease of the transition temperature of 11 K per atom % Mo was observed. The magnetic susceptibility of the low temperature phase was found to be temperature independent paramagnetic for all preparations. Electrical conductivity measurements on the same phase showed crystals with $\text{x}\text{? 0.04}$ to be semiconducting, while a metallic behavior was observed in the region $\text{0.10 ?}\text{x}\text{? 0.14}$.     

n-PbTep+−Pb1−xSnxTe heterojunctions prepared by a modified hot wall technique

$\text{n-PbTe}\text{p}{}^{\mathrm{+}}\text{?}\text{Pb}{}_{\mathrm{1?x}}\text{Sn}{}_{\mathrm{x}}\text{Te}$ heterojunctions with a long wavelength spectral cutoff (λ_c ≈ 6 μm) were prepared using the double-channel hot wall technique. The electrical and photoelectrical properties of the heterojunctions at 77, 197 and 300 K were investigated. Detectors with R_oA equal to 170 Ω cm² and a quantum efficiency of 25–40% were obtained. Reasons for the shift of the long wavelength spectral cutoff of the heterojunctions towards shorter wavelengths are given.     

Reactive plasma deposited SixCyHz films

Si_xC_yH_z films have been prepared at 200°C by reactive plasma deposition from SiH₄ and CH₄ diluted in helium in a tubular reactor. These films have a ratio s (equal to $\text{Si}\text{(}\text{Si+C}\text{))}$ ranging from 0.2 to 0.8, a refractive index ranging from 1.96 to 2.6 and an optical energy band gap in the range 2.7-2.2 eV. The total quantity of hydrogen in the film is 40% when s=0.5. Infrared analysis shows that these films have large fractions of homonuclear bonds and that this material is best described as a polymer. Mass spectrometric measurements of the gaseous products formed in the SiH₄-CH₄-He plasma have been performed and the results are related to the composition of the deposited layers.     

Core-current-enhanced domain-wall pinning in nanocrystalline Fe/sub 73.5/Cu/sub 1/Nb/sub 3/Si/sub 15.5/B/sub 7/ ribbon

We have studied the influence of surface fields H/sub p/ (generated by either direct or alternating core current) on soft magnetic properties of amorphous and nanocrystalline Fe/sub 73.5/Cu/sub 1/Nb/sub 3/Si/sub 15.5/B/sub 7/ ribbon. While in an amorphous ribbon the coercive field H/sub c/ decreases with H/sub p/, in the same optimally annealed ribbon (H/sub c/=1.3 A/m, M/sub m//spl ap/M/sub s/) H/sub c/ increases with H/sub p/ for all the explored types of H/sub p/ (static and dynamic with different phases with respect to that of the magnetizing field H). The unexpected increase of H/sub c/ in nanocrystalline ribbon is associated with the influence of H/sub p/ on the surface and main (inner) domain structure. Here, we develop a model that takes into account this influence and explains the experimental results.     

Interfacial microstructure of NiSix/HfO2/SiOx/Si gate stacks

Integration of NiSi_x based fully silicided metal gates with HfO₂ high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi_x film. Ni content varies near the NiSi/HfO_x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi_x/HfO₂ interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi_x/HfO_x was found higher than that of poly-Si/HfO₂, likely due to compositional non-uniformity of NiSi_x. No intermixing between Hf, Ni and Si beyond interfacial roughness was observed.