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Iron difluoride (FeF2) is considered a high-capacity cathode material for lithium-ion batteries. However, its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions. Herein, the conversion reaction is confined in a localized nanosized space by encapsulating FeF2 nanoparticles in polymer gelatin. The FeF2 nanocrystal-coated polyvinylidene fluoride-based layer (defined as FeF2@100%G-40%P) was synthesized by glucose-assisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process. Thanks to the improved kinetics of the localized conversion reaction, the obtained FeF2@100%G-40%P electrodes show good cyclic stability (313 mA h g−1 after 150 cycles at 100 mA g−1, corresponding to a retention of 80%) and a high rate performance (186.6 mA h g−1 at 500 mA g−1).

Metal organic frameworks (MOFs) have exhibited potential for application as heterogeneous catalytic materials because they consist of empty space, which can be used for encapsulation. Encapsulation of H3PW12O40 (HPW) in MOFs, such as the fabrication of MIL-101, by direct synthesis method or impregnation has drawn significant interest. However, few researches have used MOFs as catalysts for acetalization. This study evaluates the use of HPW encapsulated in MIL-101(Cr) to make it a catalyst in the acetalization of vanillin propylene glycol. Samples fabricated using various techniques (encapsulation and impregnation) were characterized by SEM, TEM, N2 adsorption–desorption, XRD, and FT-IR. The synthesis conditions of HPW@MIL-101 and their effects on vanillin conversion were examined. The reaction kinetics was also investigated under optimal conditions. Vanillin conversion showed that introducing HPW directly into MIL-101(Cr) during synthesis induced a 14% increase, compared with impregnation. The results indicated that HPW@MIL-101(Cr) is an effective method for vanillin propylene glycol acetal production and is reusable.

Lithium-sulfur (Li-S) batteries, as a prospective energy storage system, are still plagued by many problems that prevent them from their application, especially the low content of sulfur in the cathode. Herein, a cathode material with S up to 93 wt % is designed via a hollow donor-π-acceptor heterosystem, which combines catalytic sites, adsorption sites, and good conductivity together. Following this guidance, a hollow porous carbon sphere is prepared with CoO particles and single V atoms decorated on it (Co/V-HPCS), providing ultrahigh volumetric space for sulfur. Even the electrode made of sulfur-loaded Co/V-HPCS (Co/V-HPCS@S) has a high content of 90 wt % (sulfur content in the electrode is ∼83.5 wt %), and the cathode exhibits an excellent discharge capacity of 575.2 mAh g-1 under 0.2C after 100 cycles. With careful analysis by means of a high-resolution transmission electron microscope (HRTEM), the catalytic amounts of CoO particles and single V atoms loaded on the carbon shell are confirmed, which endows the material with outstanding catalytic ability to transfer sulfur and excellent adsorption of polysulfides. This concept of the cathode material increases the possibility of advanced long-life Li-S batteries with high tap density and high energy density.

To investigate the effect of the raw material composition on the nano-adhesive characteristics of styrene-butadiene-styrene (SBS) copolymer-modified bitumen, force-distance curves were obtained to examine the nano-adhesive forces of SBS-modified bitumen samples prepared using different virgin bitumen types, SBS modifiers, an extraction oil, and a stabilizer using atomic force microscopy (AFM). The influence of the composition of the raw materials, such as the virgin bitumen, SBS modifier, extracting oil, and stabilizing agent contents, on the cohesive characteristics were discussed for SBS-modified bitumen. The results show that force-distance curves obtained using AFM can be used to gain insight into nano-adhesive forces of SBS-modified bitumen samples. The force-spectrum technique using AFM can be used to obtain the nano-adhesive forces of the SBS-modified bitumen samples. Neat bitumen has good compatibility with a SBS modifier, which is suitable for forming SBS-modified bitumen with an increased nano-adhesive force. The nano-adhesive force of the branched-shaped SBS-modified bitumen was larger than that of linear-shaped SBS-modified bitumen. The nano-adhesive force of SBS-modified bitumen increased as the SBS modifier and stabilizer contents increased. The nano-adhesive force of the SBS-modified bitumen decreased when the extraction oil content increased.

Boron carbide (B4C) is an important type of neutron radiation shielding material with relatively high efficiency due to the high content of 10B element. Incorporation of B4C particles into polymer to prepare high-performance neutron radiation shielding material has become more and more important for the safe operation of nuclear power in the defense industry and nuclear power plant. The polyimide/B4C composite films with different micro-sized B4C contents were successfully prepared by in-situ polymerization. Silane coupling agent KH550 was employed to functionalize B4C particles to improve the dispersion of B4C particles in the polyimide matrix with strengthened interfacial interaction. As shown that the micro-sized B4C functional particles can be well dispersed in the BPDA/ODA polyimide matrix. With the B4C content increase, thermal stability of the polyimide/B4C composite films can be significantly improved, even mechanical properties partly declined. Meanwhile, the polyimide/B4C composite films exhibit good thermal neutron radiation shielding properties. The neutron permeability I/I0 changes exponentially with the change of B4C content. When the B4C content is increased to 30 wt%, the polyimide/B4C composite films show optimum properties combination with thermal decomposition temperature (Td10) of 622 °C, neutron permeability (I/I0) of 0.24 (800 μm in thickness), and tensile strength of 406 MPa. The composite thus shows great potential for use in applications which require materials with high thermal stability and neutron radiation shielding ability, such as fusion reactor system and nuclear waste disposal.

In this study, a warm red phosphor based on the substitution of Ge4+ for Ti4+ in the lattice of Mg2TixGe1−xO4:Mn4+ was prepared by a solid-state reaction route. Ge4+ acts to distort the structure of Mg2TiO4 and enhances the photoluminescence, thermal stability, quantum yield and lifetime decay significantly. The sample with the replacement of Ti by 0.35 mol of Ge, i.e., Mg2Ti0.65Ge0.35O4:Mn4+, shows efficient excitation and emission; its excitation and photoluminescence intensities are over 2.5 and 2.7 times higher than those of the Mg2TiO4:Mn4+ phosphor and its CIE coordinates moved to a warm color. Moreover, Mg2Ti0.65Ge0.35O4:Mn4+ shows better thermal stability and higher quantum yield. The integrated PL intensity at 150 °C is still 80.2% of that measured at room temperature under 330 nm light excitation. The internal quantum yield of Mg2Ti0.65Ge0.35O4:Mn4+ was 77.8%, while that of the sample without Ge4+ was 32.3%. The underlying mechanisms behind the optical changes on adjusting the cation composition of the phosphors are revealed, and the crystal field strength and the Racah parameters are estimated for Mn4+ in the Mg2TiO4:Mn4+ lattice. The luminescence mechanism was explained by the Tanabe–Sugano energy level diagram of the Mn4+ ion. These results imply that Mn4+-doped Mg2Ti0.65Ge0.35O4:Mn4+ is a promising candidate as a warm red phosphor for near-UV and blue light emitting diodes.

Lithium–sulfur batteries are currently attracting wide interest due to their high theoretical capacity, although their energy density is greatly limited by the low tap density of traditional C/S cathode materials. Herein hollow VO2@S microspheres were designed as cathode materials with high volumetric capacity by combining the intercalation and conversion mechanisms. The hollow microsphere can offer enough space for high sulfur loading, which results in a high tap density of 1.64 g cm−3, while VO2 can offer additional capacity by Li intercalation reactions and has strong interactions with polysulfides to prevent the shuttling effect by its in situ surface sulfidation. Therefore, the obtained materials delivered a high volumetric capacity (1084 mA h cm−3 at 0.1C) and good rate capability and cycling performance (440 mA h g−1 at 1.0C after 200 cycles). This study demonstrates that traditional cathode materials with a proper potential window would be an alternative host for sulfur to offer additional capacity and increase the energy density due to their high tap density.

Wire bond is the most common inter-connection method used to connect microchips to the terminals of a chip package. Wire bond reliability is vital to the performance of packaging device. It is vital to understand the reliability performance of different wire types under the environment of temperature, moisture and voltage bias. In this study, copper (Cu), palladium coated copper (PdCu) and silver (Ag) wires were boned to aluminum (Al) bond pad. Chlorine (Cl) and sulfur (S) contaminations were purposely introduced to epoxy molding compound (EMC) to accelerate the corrosion process. Reliability tests bHAST (biased highly accelerated stress test), pressure cooker test (PCT) and temperature cycle test (TCT) were conducted. The results showed that bHAST encountered most failures, followed by PCT. Whilst TCT encountered no failure. For the wire type, PdCu-75%Pd coverage showed the best reliability performance among all the legs. For the EMC contamination type, Cl played a significant role on wire bond reliability. Whilst, S did not impact much on wire bond reliability.

Wire bond is the most common inter-connection method used to connect microchips to the terminals of a chip package. Wire bond reliability is vital to the packaging device performance. The work here investigated and compared the wire bond reliability performances of bare copper (Cu), palladium coated copper (PdCu) and silver (Ag) wires on aluminum pad. For PdCu, different Pd distributions on bonded ball and their effects on PdCu corrosion resistance were studied in detail. Chlorine (Cl) and sulfur (S) contaminations were purposely introduced to epoxy molding compound (EMC) to accelerate the corrosion process. bHAST (biased highly accelerated stress test) was conducted to see the reliability performance of Cu, PdCu, Ag wires under Cl and S environment. The results showed that Cl played a significant role on wire bond reliability. Whilst, S did not impact much on wire bond reliability. The failure mechanisms were studied. It was found that poor Pd coverage on bonded ball led to poor reliability performance. On the other hand, excessive Pd accumulation on the bonded ball bottom will deteriorate the reliability performance.

Leadframe based micro-electronic packages are widely used in the semiconductor industry. The metal leadframe surface properties directly impact its adhesion with epoxy molding compound (EMC). During the manufacturing process and application services, the electronic packages unavoidably suffer from moisture and heat stress. When the moisture in the package volatilizes during the reflow process, its force may be strong enough to break the adhesion between the leadframe and EMC, causing interfacial delamination. In addition, the leadframe surface inevitably oxidized (especially Cu surface) under high thermal loading during the assembly process, and the thickness of metal oxides layer could rise quickly at such high temperature operation. The thick metal oxides layer may deteriorate the interfacial strength between leadframe and EMC, leading to higher tendency of package delamination after stressed The work here evaluated an innovated leadframe surface treatment method called NEAP, with which the copper surface of leadframe was first covered with a thin layer of silver, and then the silver surface was further chemically treated to form a special oxidization film to act as an adhesion promoter for EMC. The NEAP leadframe was compared with the conventional copper leadframe (selective silver) and rough copper leadframe, in terms of its package level reliability. Under severe thermal loading conditions, most of the leadframes could not survive the reliability tests and showed package delamination. On the contrary, the NEAP leadframe show outstanding adhesion performance compared to the others. The NEAP process concept was discussed in detail. The NEAP leadframe is suggested for use in micro-electronic packages that require high thermal performance.

Metallic 1T layered disulfides ultrathin layers fabricated by the chemical exfoliation of 2H bulk via “top-down” method are highly attractive for energy storage because of their special metallic characteristics. However, the spontaneous transformation of 1T phase to the thermodynamically stable 2H phase is detrimental to electrochemical performance. In contrast to alkali metals, transition metals can efficiently stabilize 1T layered disulfides due to their stronger ionic potential and polarizability. Herein, Co stabilized metallic 1T MoS 2 monolayers with largely distorted structure (1T d Co MoS 2 ) are designed and synthesized via a “bottom-up” method, in which Co exists on the surface of S Mo S monolayers via Co S bonds, rather than substituting Mo. Its unique structure endows the improved thermal stability and higher conductivity over pristine 1T MoS 2 , and the obtained materials exhibit an enhanced specific capacitance of 454 F g −1 (∼100 F g −1 of pristine 1T MoS 2 ) at 0.5 A g −1 and a long cyclic stability with the capacitance retention of approximately 100% even after 25,000 cycles at 10 A g −1 .

Layered transition metal dichalcogenides are promising as lithium and/or sodium storage materials for lithium and sodium (Li/Na) ion batteries. However they always exhibit limited rate capability and long-term cycling stability, due to the fact that their 2D structures are easily restacking and agglomeration during cycling process and further result poor electrochemical reversibility. Herein, hierarchical Co1/3Mo2/3S2/graphene nanocomposites without CoSx and MoS2 impurities have been synthesized via one-pot solvothermal process. The incorporation of Co into MoS2 at atomic level can not only give rise to thinner and smaller nanosheets in the nanocomposites than MoS2/graphene nanocomposites, but also significantly decrease the size of in-situ formed MoS2/CoSx nanoparticles during electrochemical conversion process, which can greatly promoting the ion diffusion and suppressing the aggregation of active materials. Furthermore, the conductivity of Co1/3Mo2/3S2/graphene nanocomposites can be enhanced from 0.46 S m−1 (MoS2/graphene) to 1.39 S m−1 via changing the semiconducting MoS2 to metallic Co1/3Mo2/3S2. The simultaneously optimized electron conductivity and ions diffusion dynamics of Co1/3Mo2/3S2/graphene nanocomposites can effectively improve the reversibility of electrochemical conversion reactions. A capacity of 940 mAh g−1 and 529 mAh g−1 can be maintained at 3200th cycle (2 A g−1) in lithium-ion batteries and 200th cycle (1 A g−1) in sodium-ion batteries, respectively.

The field emission cathode coating of nano-diamond on titanium substrate was prepared by electrophoretic deposition, the hydrogen plasma process was carried out after heat treatment, and then the microstructure, field emission properties and the luminescence performance of the samples were characterized. The results show that the adsorption of H + and the etching of H + collectively affect the morphology of diamond coating. Deficient hydrogen treatment can't reach the requirement and excessive hydrogen treatment can lead to serious etching for the diamond coating, resulting in worse field emission properties of the coating and luminescence effect. The appropriate hydrogen treatment is helpful to improve the field emission properties and luminescence effect. Finally, the field emission mechanism of nano-diamond coating on titanium substrate was discussed, and the reasons of luminescence effect difference were explained.

Nanomaterials have recently been extensively investigated for novel flexible device applications, especially in wearable and medical electronics. As an appealing form of graphene, crumpled graphene has some excellent features like ultra-thin, high stretchability, ease to fit human skin, tunable transparency and wettability. However, the fabrication process seriously limited its practical use. Here we propose a new method to transfer crumpled graphene to various substrates like PDMS, EcoFlex and GaAs, SiO 2 wafers, which makes some new applications become possible. Moreover, the electric response of crumpled graphene under strain was extensively investigated. Crumpled graphene with good linear resistance-strain behavior and large stretchable range was obtained and used as strain sensors for human motion monitoring. High performance strain sensing was achieved featuring large stretchable range, high reliability, biocompatible construction and the ability to integrate with other devices.

Transition metal sulfides with high specific capacity have received increasing research interest in lithium storage. However, the low reversibility of metal sulfides usually leads to the oxidation of Li2S into polysulfides. The dissolution of polysulfides will suppress the regeneration of sulfides due to the loss of Li2S, which usually leads to poor cycling stability of sulfides. Herein, Al2O3 coated Ni3S4 nanoparticles (Ni3S4@Al2O3) have been rationally designed and fabricated via a one-pot hydrothermal process. The regeneration of nickel sulfides, which is the key to cycling stability of sulfides, can be promoted by the localized conversion from metal to metal sulfides because the Al2O3 layer can prevent the diffusion and dissolution of polysulfides. The conversion of Al2O3 to ion-conductive AlF3 can enhance the quick charge transfer process of the lithium ion insertion/extraction reaction. Furthermore, the Al2O3/AlF3 layer can also prevent the growth and aggregation of Ni3S4 nanoparticles to retain the structure of the electrodes during the cycling process. The as-prepared Ni3S4@Al2O3 exhibits a high reversible capacity of 651 mA h g−1 at 500 mA g−1 even after 400 cycles. This method can also be extended to other metal sulfides for improving electrochemical performances.

Copper (Cu) wire is a good alternative to expensive gold (Au) wire for wire bonding interconnects in many semiconductor and microelectronic applications. However, Cu wire does pose some challenges, like it is harder than Au wire and it easily oxidize in air especially with moisture. Cu oxide layer is not a passivation layer and it will continue to grow. The Cu oxide will hinder the adhesion between wire and pad and lead, causing non-stick-on-pad (NSOP) and non-stick-on-lead (NSOL). Therefore, the shelf life and floor life of Cu wire is much shorter than that of Au wire, and special package and storage techniques are needed for Cu wire. Normally, Cu wire floor life is about 7 days, which means the wire can last for 7 days in clean room after opening the vacuum package.In this work, a batch of Cu wires were found to be severely oxidized in a production clean room, where they were open and hung on the wire bonder after 2-3 days. Surface analysis was conducted on the problematic wire. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and X-ray Fluorescence Spectrometer (XPS) are employed to identify the corrosion products on the Cu wire. The results show that the corrosion products are CuCl and CuO. It is suspected that the chloride (Cl) may come from the Cl-contained floor detergent. Simulation test was conducted to verify the contamination source in the production clean room, and the simulation results match well with the actual results. It is suggested that the assembly houses should use Cl-free detergent in the production room to prevent potential Cl contamination.

Wire bond industry is transitioning from Au (gold) bonding wire to Cu (copper) bonding wire, due to the high cost of Au and comparatively much lower cost and good electricity conductivity of Cu. Whilst Cu is less reliable than Au. Cu is susceptible to corrosion especially under the presence of moisture and Cl (chloride). In this work, Au and Cu wires were ball bonded to Al pad and molded with EMC (epoxy mold compound) with different ranges of Cl. Cl was purposely added into EMC to trigger the failure. All EMC samples were prepared with pH range of 5 – 7. Reliability tests bHAST (biased highly accelerated stress test) and HTS (high temperature storage test) were conducted. The results showed that under dry condition, Cl was not easy to attack the wire bond, and failure did not occur unless high content of Cl (up to 500ppm) was present. On the contrary, under humid environment, even several ppm content of Cl would cause failure of Cu-Al wire bond. By comparison, under humid environment, as Au-Al wire bond formed corrosion products which locked the Cl, therefore Cl could not repeatedly serve as a catalyst. Au-Al failure occurred only with high ppm content of Cl (up to 500ppm). In addition, it is found that Cl will promote the Au-Al IMC growth in HTS and bHAST.

The dopant detection limit of SIMS instrument is a critical factor in semiconductor implant process monitoring and control. However, after various substrates are tested in the chamber, possible cross-contamination may lead to change of the detection limit, resulting in the inaccurate measurements and conclusions. In this paper, the cross-contamination effect is simulated with Phosphorus contaminant sputtered over the SIMS chamber. The degree of the cross-contamination is quantified and correlated with the detection limits. One of the failure cases is schematically illustrated and studied.

Aluminum (Al) has been used as an interconnection material for the last 40 years. As the ultra-largescale integrated devices become more and more smaller, there are demands for the semiconductor gate performance to be improved through the use of a higher drive current and a lower junction capacitance. One attempt is to replace the conventional Al interconnection with copper (Cu), as Cu has lower electrical resistivity and enhanced electromigration resistance. Thermosonic wire bonding has been extensively developed and applied in bonding technique. It uses both heat and ultrasonic energy to obtain a solid-state diffusion between the bonded ball and pad. For the traditional Al bond pad, it naturally forms a passivation layer, alumina (Al 2 O 3 ), on the surface. The Al 2 O 3 prevents the continual oxidation of Al pad, and this brittle Al 2 O 3 layer is broken by the ultrasonic energy during the thermosonic bonding. However, for the Cu pad, it is well known that it readily oxidizes at air atmosphere, especially with moisture, as Cu oxide is not a passivation layer and it will continually grow, which block the subsequent solid diffusion during wire bond process. Therefore, it is necessary to study the behavior of Cu pad IMC. In this paper, gold (Au) wire was thermosonic bonded to Cu pad. The IMC (intermetallic compound) coverage was characterized. HTS (high temperature storage) study was conducted and a comprehensive study on the interfacial behavior of thermally aged Au-Cu was conducted using transmission electron microscopy. It was found that Au-Cu IMC grew slower than that of Au-Al and Cu-Al, and the thickness of Au-Cu is 100-250nm after HTS 150°C, 1000 hours.

Polythioetherimides (STPI) were first synthesized from 3- and 4-chlorophthalic anhydrides, and 4,4’-oxydianline and 1,3-bis(4-aminophenoxy) benzene by a two-step poly- condensation procedure via their soluble poly (amic acid) precursors. Then a series of isomeric polythioetherimides/polyetheretherketone (STPI/PEEK) blends samples with compositions (wt%) of 30/70, 40/60 and 50/50 were prepared and characterized. The structure characterization of STPI demonstrated by FTIR, Raman and elemental analysis show that there are little S-S bonds of the copolythioetherimides chains. Thermal, rheological, ultrasonic nondestructive testing technique, mechanical measurements and dynamic thermomechanical analysis were conducted to process and assess the morphology and mechanical properties of the STPI/PEEK blends, and 30/70 weight composition of STPI/PEEK was preferred. There are few voids or air gaps in the molding samples. The samples of STPI/PEEK-30/70 show two relaxations at 164.2 °C and 243.5 °C, an average tensile modulus of 1.264 GPa, an average bending elastic modulus of 2.061 GPa and a bending strength of 78.3 MPa. Finally, the friction-wear characteristics of STPI/PEEK composites with solid lubricants such as graphite, MoS2 and PTFE were investigated, indicating a promising way to develop a STPI-based thermoplastic for tribological applications.

LDHs in atomic thickness (mono-/bi-layers) usually exhibit novel physicochemical properties, especially in surface-dependent energy storage and catalysis areas. However, the thickness of the commonly reported 2D LDHs is in nanoscale and the bottom-up synthesis of atomically thin LDHs is rarely reported. Herein, high-quality atomically thin layered NiFe-LDHs assembled 3D microspheres were synthesized via a rational designed reaction system, where the formation of atomically thin building blocks was controlled by the synergetic effects of released carbonate anions and butanol. Furthermore, the complexant and solvents played important effects on the process of coprecipitation and the assembling of LDHs. Due to the nature of atomically thin LDHs nanosheets and unique 3D hierarchical structures, the obtained microspheres exhibited excellent electrocatalytic oxygen evolution reaction (OER) activity in alkaline medium with an onset overpotential (0.435 V, which is lower than that of common LDHs) and good durability. The as-prepared 3D NiFe-LDHs microspheres were also firstly used as supercapacitor materials and displayed a high specific capacitance of 1061 F g −1 at the current density of 1 A g −1 .

The ability to continuously and reversibly tune the band gap and the strain-photonic coupling effect in optoelectronic materials is highly desirable for fundamentally understanding the mechanism of strain engineering and its applications in semiconductors. However, optoelectronic materials (i.e., GaAs) with their natural brittleness cannot be subject to direct mechanical loading processes, such as tension or compression. Here, we report a strategy to induce continuous strain distribution in GaAs nanoribbons by applying structural buckling. Wavy GaAs nanoribbons are fabricated by transfer printing onto a prestrained soft substrate, and then the corresponding photoluminescence is measured to investigate the strain-photonic coupling effect. Theoretical analysis shows the evolution of the band gap due to strain and it is consistent with the experiments. The results demonstrate the potential application of a buckling configuration to delicately measure and tune the band gap and optoelectronic performance.

A core-shell Cu-benzene-1,3,5-tricarboxylic acid (Cu-BTC)@TiO2 was successfully synthesized for photocatalysis-assisted adsorptive desulfurization to improve adsorptive desulfurization (ADS) performance. Under ultraviolet (UV) light irradiation, the TiO2 shell on the surface of Cu-BTC achieved photocatalytic oxidation of thiophenic S-compounds, and the Cu-BTC core adsorbed the oxidation products (sulfoxides and sulfones). The photocatalyst and adsorbent were combined using a distinct core-shell structure. The morphology and structure of the fabricated Cu-BTC@TiO2 microspheres were verified by scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, X-ray powder diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy analyses. A potential formation mechanism of Cu-BTC@TiO2 is proposed based on complementary experiments. The sulfur removal efficiency of the microspheres was evaluated by selective adsorption of benzothiophene (BT) and dibenzothiophene (DBT) from a model fuel with a sulfur concentration of 1000 ppmw. Within a reaction time of 20 min, the BT and DBT conversion reached 86% and 95%, respectively, and achieved ADS capacities of 63.76 and 59.39 mg/g, respectively. The BT conversion and DBT conversion obtained using Cu-BTC@TiO2 was 6.5 and 4.6 times higher, respectively, than that obtained using Cu-BTC. A desulfurization mechanism was proposed, the interaction between thiophenic sulfur compounds and Cu-BTC@TiO2 microspheres was discussed, and the kinetic behavior was analyzed.

Aluminum (Al) has been used as an interconnection material for the last 40 years. As the ultra-large-scale integrated devices become more and more smaller, low junction capacitance and higher drive current are measures to improve the performance of semiconductor gate. One attempt is to replace the conventional Al interconnection with copper (Cu), as Cu possesses improved electromigration resistance, lower electrical resistivity and higher thermal conductivity. The front-end change, however, brings concerns to back-end process, probe and later wire bond process on a readily oxidized Cu surface. Questions like the Cu pad oxidation during handling, wafer dicing, die attach and thermosonic bonding are concerns. This review summarizes the current literature on Cu pad, including its manufacturing methods, advantages, disadvantages, oxidation prevention measures, wire bond process and wire bond reliability. It will provide guidance for the work relevant to Cu pad.

Polycrystalline semiconductor or metal materials are characterized with numerous grain boundaries between neighboring grains. The grain boundaries show a high degree of mismatch of grain orientation and a less efficient atomic packing. Aggressive ions can diffuse much more easily within grain boundaries; rendering the zone susceptible to oxidation and corrosion, which are one of the root causes for electronic device failures. Therefore, revealing the compositional distribution of grain boundaries can help researchers better understand and improve the chemical, physical and electrical properties of materials. This paper mainly focuses on material characterization of the corroded material, providing useful methods for physical failure analysis in real devices which will be discussed in our future work. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is one of the most sensitive techniques for materials analysis. One of its powerful capabilities is to provide 3D images of testing material, demonstrating elemental distribution and microstructure of polycrystalline materials. In this work, common polycrystalline materials used in semiconductors (polysilicon) and metal alloys (304 steel) were studied. TOF-SIMS 3D imaging was used to monitor the diffusion path of moisture and corrosive ions via the grain boundaries. The results indicate that the grain boundaries are vulnerable to attacks of moisture and corrosive ions (CI)

Partial discharge detection is crucial for electrical cable safety evaluation. The ultrasonic signals frequently generated in the partial discharge process contains important characteristic information. However, traditional ultrasonic transducers are easily subject to strong electromagnetic interference in environments with high voltages and strong magnetic fields. In order to overcome this problem, an optical fiber Sagnac interferometer system is proposed for partial discharge ultrasound detection. Optical fiber sensing and time-frequency analysis of the ultrasonic signals excited by the piezoelectric ultrasonic transducer is realized for the first time. The effective frequency band of the Sagnac interferometer system was up to 175 kHz with the help of a designed 10 kV partial discharge simulator device. Using the cumulative histogram method, the characteristic ultrasonic frequency band of the partial discharges was between 28.9 kHz and 57.6 kHz for this optical fiber partial discharge detection system. This new ultrasound sensor can be used as an ideal ultrasonic source for the intrinsically safe detection of partial discharges in an explosive environment.

The application of non-toxic carriers to increase drug loading, multi-drug delivery, and extremely small size of nano-drugs to construct a tremendous transmission system is the goal for all researchers to be pursued. The proposal of natural pectin nano-platform for delivery of multiple drugs is critical for biomedical research, especially a particle size of below 100nm with high yield. Here we design a new core-shell structure pectin-eight-arm polyethylene glycol-ursolic acid/hydrooxycampothecin nanoparticle (Pec-8PUH NPs) through a special self-assembly method for stabilizing and dispersing particles, improving water-solubility, and achieving drug controlled release. The obtained Pec-8PUH NPs possessed appropriate size (~91nm), drug-loaded efficiency and encapsulation efficiency through the regulation of eight-arm polyethylene glycol. In addition, Pec-8PUH NPs could enhance cell cytotoxicity, shorten blood retention time (7.3-fold UA, 7.2-fold HCPT) and more effective cellular uptake than free drugs, which exhibited an obvious synergistic effect of UA and HCPT by the co-delivery. 4T1 tumor-bearing mice also showed a higher survival rate than free UA and free HCPT. The result further shows that this novel drug delivery system has a promising potential for anti-cancer combination therapy.

TEMJEDX analysis techniques are widely used in failure analysis. Based on TEM results, one can know the structures of the sample e.g. in anomalous or crystalline, as well as the thickness of the thin film layer. Typically, TEM/EDX results can only provide the elemental information of the sample. In this paper, we discussed a standardless EDX analysis method to identify the chemical state composition for an unknown sample. Generally, it is to use the atomic percentage Wia' (excluding Pt from the sample preparation), which can be easily achieved by a certain data processing, to identify the chemical state composition. For example, in this paper, we studied the layers composition on Cu substrate, which was consisting of CuO and CuiO.

CoFe2O4-graphene nanosheets (CoFe2O4-GNSs) were synthesized through an ultrasonic method, and their electrochemical performances as Li-ion battery electrode were improved by annealing processes. The nanocomposites obtained at 350 °C maintained a high specific capacity of 1,257 mAh g−1 even after 200 cycles at 0.1 A g−1. Furthermore, the obtained materials also have better rate capability, and it can be maintained to 696, 495, 308, and 254 mAh g−1 at 1, 2, 5, and 10 A g−1, respectively. The enhancements realized in the reversible capacity and cyclic stability can be attributed to the good improvement in the electrical conductivity achieved by annealing at appropriate temperature, and the electrochemical nature of CoFe2O4 and GNSs during discharge–charge processes. CoFe2O4-graphene nanocomposites (CoFe2O4-GNSs) have been synthesized through an ultrasonic method combined with calcination process. The nanocomposite calcinated at 350 °C shows better rate capabilities, e.g., 696, 495, 308, and 254 mAh g−1 at 1, 2, 5, and 10 A g−1, respectively.

Polydopamine (PDA) functionalized graphene/NiFe 2 O 4 (GNSs–PDA–NiFe 2 O 4 ) nanocomposite has been successfully synthesized through an in-situ ultrasonic method. The obtained GNSs–PDA–NiFe 2 O 4 nanocomposite shows a reversible capacity up to 947 mAh g −1 and much improved rate capability, e.g. delivering a capacity of 562 mAh g −1 at 5 A g −1 , about 7 times higher than that of graphene/NiFe 2 O 4 nanocomposite. The improvement in the rate capability of the obtained GNSs–PDA–NiFe 2 O 4 nanocomposite can be attributed to the improved interactions between graphene and NiFe 2 O 4 derived from PDA, and a high conductive network fabricated by PDA functionalized graphene, which can be supported by TEM images and EIS measurements. Further studies reveal the strong graphene–NiFe 2 O 4 interactions are also beneficial for retaining the high conductive network after the charge–discharge processes, and further beneficial for its cyclic stability.

The composite piezomagnetic film was prepared by using Fe73.5CulNb1.5Si13.5B9Mo1.5 amorphous powder with particles size of 40 μm as dispersing agent and silicon rubber as the matrix. Meanwhile, the Fe73.5CulNb3Si13.5B9 amorphous ribbon was selected as piezoelectric layer. The testing frequency was ranged from 10 kHz to 1 MHz, and the pressure stress was from 0 to 0.14 MPa. The tiny stress impedance (TST) effects of the two types of layer structures were compared in the experiment, the two types included piezomagnetic/piezoelectric/piezomagnetic (pm/pe/pm) layer and piezoelectric/piezomagnetic/piezoelectric (pe/pm/pe) layer. It is found that both of the layer structures have magnetoelectricity coupling effects. The magnetoelectricity coupling effect enhances with the increase of pressure stress before 0.02 MPa, and afterward the magnetoelectricity coupling effect comes to a maximum value, which has little contribution to TSI. Since two types of layer structure are both of varying magnetoelectricity coupling effect, pm/pe/pm is piezomagnetic based and pe/pm/pe is piezoelectric based.

Three-dimensional (3D) flower-like Co–Al layered double hydroxide (Co–Al-LDH) architectures composed of atomically thin nanosheets were successfully synthesized via a hydrothermal method in a mixed solvent of water and butyl alcohol. Owing to the unique hierarchical structure and modification by butyl alcohol, the electrochemical stability and the charge/mass transport of the Co–Al-LDHs was improved. When used in supercapacitors, the obtained Co–Al-LDHs deliver a high specific capacitance of 838 F g−1 at a current density of 1 A g−1 and excellent rate performance (753 F g−1 at 30 A g−1 and 677 F g−1 at 100 A g−1), as well as excellent cycling stability with 95% retention of the initial capacitance even after 20,000 cycles at a current density of 5 A g−1. This work provides a promising alternative strategy to enhance the electrochemical properties of supercapacitors. Electronic supplementary material The online version of this article (doi:10.1007/s40820-016-0121-5) contains supplementary material, which is available to authorized users.

3D packaging with complex multi die and multi component structure has new Failure Analysis challenges in electrical testing, package fault isolation and physical failure analysis. This paper emphasize on new approach using 3D X-Ray other techniques.

In the authors' previous papers, the failure mechanism and elimination solutions of galvanic corrosion (Al-Cu cell) on microchip Al bondpads in the Al process (0.18un and above) have been studied [1-2]. In this paper, the authors will further study the failure mechanism and root cause of galvanic corrosion (Al-Cu cell) on microchip Al bondpads in the Cu process (0.13um and below) with Ta barrier metal. Based on our results, the root cause of galvanic corrosion (Al-Cu cell) in the Al process is only one way and Al-Cu cell is from Al alloy (Al + 0.5%Cu) on Al bondpads. However, in the Cu process it may be from two ways and Al-Cu cell can be from both Al alloy (Al + 0.5%Cu) on Al bondpads and the Cu metal layer below the barrier metal Ta when Ta has weak points or pinhole. As such, the pinhole defects on Al bondpad caused by galvanic corrosion (Al-Cu cell) in the Cu process might be more serious than that in the Al process. In this paper, TEM is used for root cause identification. Based on the TEM results, galvanic corrosion was due to the weak point/pinhole at the Ta barrier metal layer and Al-Cu diffusion.

Ultrasonic Assisted SILAR method (UA-SILAR) was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films were analyzed by means of XRD and SEM. Moreover, the underling deposition mechanism of ZnO films was discussed. Results show that obtained ZnO films exhibit an excellent crystallinity with the preferential orientation of (002) plane. The crystalline grain of films is about 40nm in size, which is supported by both the Sherrer equation and the SEM result. However, the ZnO film is composed of numerous clustered particulates in the size of 200 to 300nm, and each particulate is the compact aggregation of smaller ZnO crystalline grains. It is speculated that the excellent crystallinity of ZnO films may chiefly originate from the cavatition effect of the ultrasonic rinsing process.

Flexible and stretchable optoelectronics, built-in inorganic semiconductor materials, offer a wide range of unprecedented opportunities and will redefine the conventional rigid optoelectronics in biological application and medical measurement. However, a significant bottleneck lies in the brittleness nature of rigid semiconductor materials and the performance's extreme sensitivity to the light intensity variation due to human skin deformation while measuring physical parameters. In this study, the authors demonstrate a systematic strategy to design an epidermal inorganic optoelectronic device by using specific strain-isolation design, nanodiamond thinning, and hybrid transfer printing. The authors propose all-in-one suspension structure to achieve the stretchability and conformability for surrounding environment, and they propose a two-step transfer printing method for hybrid integrating III-V group emitting elements, Si-based photodetector, and interconnects. Owing to the excellent flexibility and stretchability, such device is totally conformal to skin and keeps the constant light transmission between emitting element and photodetector as well as the signal stability due to skin deformation. This method opens a route for traditional inorganic optoelectronics to achieve flexibility and stretchability and improve the performance of optoelectronics for biomedical application.

In the wafer fabrication (fab) and assembly process, process underetch residue and material contamination on bondpads may cause NSOP (non-stick on pad) problem. In this paper, the root cause of 3 NSOP cases were discussed and identified by using Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) techniques. Our failure analysis results showed that the root causes were attributed to either wafer fabrication or assembly process such as Si underetch, Ni 2 O 3 contamination and tape (with PDMS) residue.

A compact thermal tactile display device with multiple heat sources is proposed in this paper. The device has a 3×3 display units array and a Peltier module. In every display unit, a wire-twined resistance is used as heat component, a minitype NTC thermistor is used as temperature sensor, and an aluminum column is used as heat conduction component for contacting. The Peltier module is used to cool the display units array. Finally, the device was installed on the hand controller, allowing operators to manipulate virtual hand to touch the heat sources in the virtual environment, and its thermal tactile display property was tested. The results showed that the thermal tactile device can display the temperature from 5°C to 55°C, and different temperature field distribution can be displayed on the contact surface of the 3×3 array.

Volumetric properties are essential for a better understanding of how to design the mixtures. Due to the irregularity of aggregate shape, these properties vary randomly with the same gradation. In this paper, the volumetric properties [bulk specific gravity (γf), air voids (VV), voids in mineral aggregate (VMA), and voids filled with asphalt (VFA)] were determined on two mixtures types, namely, A and B. These mixtures were statistically analyzed using different distribution methods. Seventy-two samples of Mixture A and 52 of Mixture B were fabricated using the Marshall design method. Results of the study showed that the Weibull distribution could reflect the probability distribution law of the volumetric properties of the mixtures. The two-parameter Weibull distribution function appears to be more appropriate or use with γf and VFA, whereas the three-parameter Weibull distribution function was most appropriate for VV and VMA. The analysis of test results also revealed that there are significant differences in the volumetric properties of the two mixtures tested at the same confidence level. The confidence interval decreases with a decrease in reliability.

Porous Zn–Sn–O nanocubes with a uniform size were synthesized through a facile aqueous solution route combined with subsequent thermal treatment. The chemical composition, morphology, and microstructure of Zn–Sn–O nanocubes, which have significant effects on the lithium storage performances, were easily tuned by adjusting the calcination temperature in preparation processes of ZnSn(OH)6 solid nanocubes. Further studies revealed that porous Zn–Sn–O nanocubes prepared at 600 °C exhibited a good rate capability and a high reversible capacity of 700 mAh g−1 at a current density of 200 mA g−1 after 50 cycles, which may be a great potential as anode materials in Lithium-ion batteries.