Modification of optical and electrical properties of ITO using a thin Al capping layer

In this study, the work function, transmittance, and resistivity of indium tin oxide (ITO) thin films were successfully modified by depositing an Al capping layer on top of ITO with subsequent thermal annealing. The 5 nm thick Al layer was deposited by a conventional dc magnetron sputtering method and the layer was converted into an aluminum oxinitride by subjecting the sample to rapid thermal annealing (RTA) under a nitrogen atmosphere. The films exhibited a high transmittance of 86% on average within the visible wavelength region with an average resistivity value of 7.9 × 10^− 4 Ω cm. Heat-treating the Al/ITO films via RTA resulted in the decrease of the optical band gap from that of bare ITO. In addition, the films showed red-shift phenomena due to their decreased band gaps when the heat-treatment temperature was increased. The resultant electrical and optical characteristics can be explained by the formation of aluminum oxinitride on the surface of the ITO films. The work function of the heat-treated films increased by up to 0.26 eV from that of a bare ITO film. The increase of the work function predicts the reduction of the hole-injection barrier in organic light-emitting diode (OLED) devices and the eventual use of these films could provide much improved efficiency of devices.     

Top emission organic light-emitting devices with CsCl capping layer

We have developed top emission organic light-emitting devices using a CsCl capping layer on top of semitransparent Ca/Ag cathode. By using a CsCl capping layer, the transmittance of top electrode can be improved by 93%. While the electrical conduction characteristic of device is not influenced by the capping layer, the current efficiency increases with increasing the transmittance of Ca/Ag/CsCl cathode. For example, as the transmittance of top electrode increases from 55 to 91% by varying CsCl thickness, the current efficiency of green fluorescent top-emitting device increases from 8 to 18 cd/A.     

Nonvolatile floating gate memory containing AgInSbTe-SiO2 nanocomposite layer and capping the HfO2/SiO2 composite blocking oxide layer

An extremely large memory window shift of about 30.7 V and high charge storage density =2.3 × 10(13) cm(-2) at ± 23 V gate voltage sweep were achieved in the nonvolatile floating gate memory (NFGM) device containing the AgInSbTe (AIST)-SiO(2) nanocomposite as the charge trap layer and HfO(2)/SiO(2) as the blocking oxide layer. Due to the deep trap sites formed by high-density AIST nanocrystals (NCs) in the nanocomposite matrix and the high-barrier-height feature of the composite blocking oxide layer, a good retention property of the device with a charge loss of about 16.1% at ± 15 V gate voltage stress for 10(4) s at the test temperature of 85?°C was observed. In addition to inhibiting the Hf diffusion into the programming layer, incorporation of the SiO(2) layer prepared by plasma-enhanced chemical vapor deposition in the sample provided a good Coulomb blockade effect and allowed significant charge storage in AIST NCs. Analytical results demonstrated the feasibility of an AIST-SiO(2) nanocomposite layer in memory device fabrication with a simplified processing method and post-annealing at a comparatively low temperature of 400?°C in comparison with previous NC-based NFGM studies.     

TiN薄膜的循环制备和电学性质

用金属有机物化学气相淀积（Metal Organic Chemical Vapor Deposition,MOCVD）制备了TiN薄膜,通过不同循环制备的、厚度相同的平面薄膜电阻率的比较研究了TiN薄膜的电学性质．结果表明,多次循环会引入界面而增大电阻率,与薄膜成分和微结构分析的结果一致．得到了单循环的最优厚度以使样品电阻率最低．通过相同循环、不同厚度样品在真实器件中电学性能的比较,发现介窗（Via）直径越小,TiN薄膜对介窗电阻的影响越大．     

界面梯度对TiN／不锈钢涂层应力的影响

气相沉积表面涂层在科学技术各领域得到广泛应用，然而，由于涂层与基体在化学和物理性质上的差异，使得涂层与基体在界面两侧产生结构和性能上的突变，影响了涂层功能的充分发挥。为此，采用多靶磁控溅射技术制备了具有梯度过渡层的ＴｉＮ／不多靶磁控溅射技术制备了具有梯度过渡层的ＴｉＮ／不锈钢涂层，并研究了梯度层对涂层内应力的影响。研究结果表明：采用多靶磁控溅射技术，分别控制各靶的功率，能够精确控制梯度层的成份变化     

Boundary layer flow with variable tensor electrical conductivity

Summary Studies are made on laminar compressible magnetohydrodynamic (MHD) boundary layer flow over an insulated wall with variable tensor electrical conductivity. The effects of the electromagnetic loading parameter, the magnetic interaction parameter and the ratio of the wall temperature to the free stream temperature on the boundary layer physical parameters have been discussed.With 3 Figures     

磁性多层膜中保护层Ru对磁性层NiFe的影响

主要研究了不同保护层Ta和Ru对磁性薄膜NiFe的厚度及磁性的影响.通过观察可以看出,NiFe/Ta,NiFe/Ru界面间产生了磁矩为零的部分层即所谓的"死层",其厚度分别为(1.5±0.2)nm,(1.2±0.2)nm(厚度误差在0.2nm范围内).利用两种保护层时虽然避免不了"死层"现象的出现,但是发现,Ru作为保护层时产生的"死层"厚度比Ta作为保护层时的小.为了进一步证实这一点,我们采用X射线衍射仪及X射线光电子能谱仪对该两种薄膜进行了结构测试和深度剖析,并且运用XPSPeak 4.1拟合软件对获得的Ta4f和Ru3d的高分辨XPS谱进行了计算机拟合分析;结果表明,Ru较Ta更加适合于做保护层,渴望在自旋电子器件上得到应用.     

Two-silicon-nanocrystal layer memory structure with improved retention characteristics

It was demonstrated in the literature that the use of self-aligned doubly-stacked Si dots improves retention characteristics of a nanocrystal memory. In this paper, we show that a similar effect may be obtained by using two distinct layers of silicon nanocrystals within the gate dielectric of the MOS structure, if the nanocrystal density in each layer is high enough (above 10(12) dots/cm2) so as to get an average effect of at least one smaller dot underneath each larger one. The relative distance of the layers and their position from the silicon substrate and the gate metal are critical for optimum memory operation. Two different double-nanocrystal-layer structures were investigated. In the first structure the two nanocrystal layers were close together and they were composed of dots of different size (lower layer: 3 nm, upper layer: 5 nm), while in the second structure the dot layers were composed of dots of equal diameter (d = 3 nm) and their inter-distance was much larger. In both cases, the retention characteristics of the structure were improved compared with a single dot layer structure. In the second case this improvement was significantly larger than in the first case. Extrapolation of the data to ten years memory operation, showed that the charge loss after this time was only approximately 12%.     

Controlled wrinkling of a thin elastic film capping a liquid layer

We perform a linear analysis to examine electric-field-induced stability of a thin film that caps a liquid layer resting on a pre-stretched soft elastic layer glued onto a rigid substrate. Our study shows that the capping film is always unstable for nonvanishing applied voltage. The undulation wavelength of the film is initially quite large, but undergoes a sharp transition when the voltage is increased to a critical value. In this case, well aligned winkles with considerably smaller wavelength appear in the fashion parallel to the tensile direction of the soft elastic layer. The magnitude of the wavelength is tunable, thus providing a mechanism to control the wrinkling pattern of the capping film.     

Mechanical and ellipsometry measurements of thin TiN layer prepared by PIII

Titanium nitrides have good mechanical, biomedical and optical properties, therefore they are used to harden and protect cutting and sliding surfaces and as a non-toxic exterior for bio-medical applications. Nitrogen plasma immersion implantation (PIII), in which the diffusion of nitrogen from low pressure r.f. plasma is combined with the implantation of nitrogen ions at energies up to 30 kV, is an effective tool for nitriding titanium and titanium alloys. In this work, samples of pure titanium were nitrided by PIII at different negative high voltage pulses. The properties and the characteristics of the processed samples were evaluated using X-ray diffraction (XRD), Auger electron spectroscopy (AES), ball-on-disk type tribometer, surface profilemeter, and ellipsometry measurements. The results show that, the wear resistance of the untreated sample in comparison to the PIII treated samples is extremely poor and the friction coefficient for the PIII treated samples is decreased to the half value in comparison to the untreated titanium, this attributed to the formation of the solid solution titanium α-Ti(N) and the cubic TiN phases. Ellipsometric measurements were carried out on the PIII treated samples at different negative high voltage pulses. A three layers model was used to fit the calculated data to the experimental ellipsometric spectra. The thickness, surface roughness and refractive index increase with increasing the negative high voltage pulses. The refractive index at 550 nm increases from 1.83 to 2.09 as the negative high voltage pulses increases from 10 to 30 kV.     

Effects of interfacial layer on characteristics of TiN/ZrO2 structures

To minimize the formation of unwanted interfacial layers, thin interfacial layer (ZrCN layer) was deposited between TiN bottom electrode and ZrO2 dielectric in TiN/ZrO2/TiN capacitor. Carbon and nitrogen were also involved in the layer because ZrCN layer was thermally deposited using TEMAZ without any reactant. Electrical characteristics of TiN/ZrO2/TiN capacitor were improved by insertion of ZrCN layer. The oxidation of TiN bottom electrode was largely inhibited at TiN/ZrCN/ZrO2 structure compared to TiN/ZrO2 structure. While the sheet resistance of TiN/ZrCN/ZrO2 structure was constantly sustained with increasing ZrO2 thickness, the large increase of sheet resistance was observed in TiN/ZrO2 structure after 6 nm ZrO2 deposition. When ZrO2 films were deposited on ZrCN layer, the deposition rate of ZrO2 also increased. It is believed that ZrCN layer acted both as a protection layer of TiN oxidation and a seed layer of ZrO2 growth.     

具有2D-EDAPbI4薄覆盖层的环境稳定的FAPbI3基钙钛矿太阳能电池（英文）

二维(2D)卤化铅钙钛矿材料是钙钛矿太阳能电池(PSC)中最有前途的吸光材料之一,具有优异的稳定性和缺陷钝化作用.然而,这些稳定的二维PSC的转换效率仍远远落后于三维钙钛矿电池.在本文中我们通过原位生长的方法将2D EDAPbI4层成功制备在3D FAPbI3层表面。这种合理设计的2D-3D钙钛矿薄膜分层结构可以明显提高电池的效率.另外,由于EDAPbI4层的高抗湿性和抑制迁移, 2D-3D电池器件显示出明显增强的长期稳定性,在200 h内一直保持初始转换效率,甚至在500 h后仍能保持其初始转化效率的90%.     

Growth and in-situ electrical characterization of ultrathin epitaxial TiN films on MgO

We examine the properties of ultrathin TiN films grown by reactive dc magnetron sputtering on single-crystalline MgO(100) substrates at growth temperatures ranging from 30 to 650 °C. The resistance of the films is measured in-situ, during growth, to study the thickness at which the films coalesce and become structurally continuous. Both the in-situ resistance measurements and X-ray diffraction measurements show a clear transition from polycrystalline growth to epitaxial (100) growth well below typical TiN growth temperatures, or between 100 and 200 °C. The coalescence and continuity thicknesses are 1.09 ± 0.06 nm and 5.5 ± 0.5 nm, respectively, at room temperature but reach a minimum of 0.08 ± 0.02 nm and 0.7 ± 0.1 nm, respectively, at 600 °C. A large drop in resistivity is seen with increasing growth temperature and the resistivity reaches 16.6 μΩ cm at 600 °C. Achieving epitaxy at such a low temperature and a low continuity thickness is important in a variety of applications such as device interconnects and metal-oxide-semiconductor devices.     

TiN/O''''-sialon复相陶瓷的常温导电性能研究

对原位TiN/O'-sialon纳米复相陶瓷(NTS)和采用"二步法"制备的TiN/O'-sialon复相陶瓷(TS)的常温导电性能进行了对比研究,并对材料TS进行了放电加工.研究结果表明,初始原料中20%(质量分数)和25%(质量分数)左右的TiO2加入量是决定材料NTS和TS中TiN能否形成导电网络的最低TiO2加入量,该导电临界值同基相O'-sialon与导电相TiN的颗粒尺寸比有关,此时相应材料的电阻率为1.6×10-2和1.8×10-2 Ω·cm,满足放电加工的需要.烧结温度升高,两种材料的电阻率略有降低.随放电加工速度的增加,材料TS加工表面粗糙度明显增加.     

Controlling of the electrical resistivity of GaN layer using AIN nucleation layer

The sheet resistance (Rs) of undoped GaN films on AIN/c-plane sapphire substrate was investigated. The Rs was strongly dependent on the AIN layer thickness and semi-insulating behavior was observed. To clarify the effect of crystalline property on Rs, the crystal structure of the GaN films has been studied using X-ray scattering and transmission electron microscopy. A compressive strain was introduced by the presence of AIN nucleation layer (NL) and was gradually relaxed as increasing AIN NL thickness. This relaxation produced more threading dislocations (TD) of edge-type. Moreover, the surface morphology of the GaN film was changed at thicker AIN layer condition, which was originated by the crossover from planar to island grains of AIN. Thus, rough surface might produce more dislocations. The edge and mixed dislocations propagating from the interface between the GaN film and the AIN buffer layer affected the electric resistance of GaN film.     

Characterization of gold nanoparticle pentacene memory device with polymer dielectric layer

We report on the electrical behavior of gold nanoparticles (Au NPs) intervened metal-pentacene-insulator-semiconductor structures. The structure adopts polyvinyl alcohol (PVA) and pentacene as gate insulator and semiconductor, respectively. On the PVA (250 nm) film which was spin-coated and UV cross-linked, 3-aminopropyl triethoxysilane was functionalized for self assembling of the Au NPs monolayer. The devices exhibited clockwise hysteresis in their capacitance-voltage characteristics, with a memory window depending on the range of the voltage sweep. A relatively large memory window of about 4.7 V, which was deduced from control devices, was achieved with voltage sweep of (−/+)7 V. Formation of the monolayered Au NPs was confirmed by field effect scanning electron microscopy and atomic force microscopy.     

An electrical probe with electron emission in the regime of a continuous medium

The influence of electron emission on the current-voltage characteristics of a cylindrical probe placed in a weakly ionized, dense plasma with constant properties and frozen-in chemical reactions is considered.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 52, No. 2, pp. 224–227, February, 1987.     

Electrical scanning probe microscopy of an integrated blocking layer

Scanning probe microscopy was performed on an integrated blocking layer system developed for hybrid organic solar cells. A nanocomposite consisting of titania and an amphiphilic triblock copolymer ((PEO)MA-PDMS-MA(PEO)) was prepared by sol-gel chemistry. After plasma treatment and annealing of a spin casted film of 30-100 nm thickness a granular structure with a typical titania grain diameter of 20 nm was found. Conductive scanning force microscopy revealed that on top of almost every grain on the surface there is an increased conductivity compared to the average value. The correlation of grains and conductivity indicated that titania particles formed interconnecting paths through the film. For the resistivity of these pathways we found that effects of tip-sample and sample-electrode resistivity dominate. Additionally, conductive scanning force microscopy revealed non-conducting structures attributed to the thermal treatment. Kelvin probe microscopy of pristine samples on one side and plasma treated plus annealed samples on the other side showed that there is a shift in work function (0.8 +/- 0.2 eV) as expected for the transition of amorphous to anatase titania.     

Reflectometric study of contaminant layer on a probe window

In this study properties of a contaminant material on the surface of a probe window (prism) were investigated. The probe window, i.e., the prism, is part of the reflectometer apparatus exploited in this study. The contaminant layer was considered to originate from a pulping solution containing lignin contacting the surface of the prism. In these experiments the contact time was up to 5.0 hours. To find the values of the contaminant material properties, i.e., refractive index (n), extinction coefficient (k), and effective thickness (d), an optical model was proposed assuming that the contaminant layer is continuous and homogenous. In addition, the model includes an inter-diffusion layer existing between the contaminant layer and the lignin solution. From the fitting procedure using the optical model of depth profiling, it was found that the growth rate of the contaminant layer was approximately 60 nm per hour. The results obtained by theory and experiments were consistent for both s- and p-polarizations and for the various wavelengths of the light source (300, 400, and 500 nm).