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A comfortable, breathable, and high-quality self-powered wearable sensor system is fabricated using a two-dimensional conductive metal–organic skeleton.

Dopant segregation (DS) technique has been extensively employed to tune Schottky barrier heights (SBHs) of NiSi/Si diodes, either leading to reduced specific contact resistivity ( $\rho _{\text {c}}$ ) in source/drain (S/D) Ohmic contacts, or enhanced current drivability in Schottky barrier S/D MOSFET (SB-MOSFET) where metallic NiSi is employed as S/D. A capacitance–voltage ( ${C}$ – ${V}$ ) method is usually adopted to reliably extract the SBHs of NiSi/Si for investigating the effectiveness of such a DS technique. In order to avoid large reverse leakage current which rules out the possibility of SBHs extraction during ${C}$ – ${V}$ measurements, dopants with opposite polarity to that in epitaxial Si substrate segregate at the NiSi/Si interface, for instance, boron DS (B DS) for NiSi/n-Si and arsenic DS (As DS) for NiSi/p-Si. This, however, raises one critical question, i.e., NiSi/p+-Si (B DS)/n-Si and NiSi/n+-Si (As DS)/p-Si are p-n or Schottky junctions. In this work, a dedicated circuit is devised to distinguish the type of as-fabricated NiSi/Si diodes with DS based on different switching mechanisms between p-n and Schottky junctions.

Capacity fading of Li-rich cathodes in the cycling process is mainly caused by the irreversible side reactions at the interface of electrode and electrolyte by reason of the lack of a corrosion resistant surface. In this work, isocyanate-related functional groups (-N═C═O groups and polyamide-like groups) were tightly bonded on the surface of Li-rich oxides through a urea decomposition gas heat-treatment. The surface isocyanate functionalization inhibits the side reaction of PF5 hydrolysis to give LixPFyOz and HF species at the surface of Li-rich materials in the cycle process. As compared to the untreated Li-rich sample U0, the samples with the spinel-like layer and isocyanate functionalized surface exhibited an enhanced cycle stability. The capacity retention of the treated sample U3 reached as high as 92.6% after 100 cycles at the current density of 100 mA/g, larger than 66.8% for the untreated sample. Even at a higher current density of 1000 mA/g, sample U3 gives a capacity retention of 81.7% after 300 cycles. The findings of this work reveal the importance of surface isocyanate functionalization in restraining the surface side reactions and also suggest an effective method to design Li-rich cathode materials with better electrochemistry performance.

Li-rich layered oxide materials are promising cathode materials for lithium ion batteries because of their high capacity and low cost. Nevertheless, the lack of a stable surface structure to suppress surface side reactions and layered-to-spinel transitions and thus rapid capacity fading is a critical problem that hinders the widespread practical applications of Li-rich layered oxide materials. In this work, a stable coating layer of LiF/LixPFyOz was introduced on the surface of Li-rich particles by a LiPF6-electrolyte-solvothermal process followed by post-sintering treatment. In the solvothermal process, the LiPF6-based electrolyte reacts with surface residues (such as H2O and Li2CO3) moderately at 80 °C, and then a thin LiF/LixPFyOz protective layer is formed. The LiF/LixPFyOz protective layer is tightly chemically bonded to the surface of Li-rich particles inhibiting surface side reactions and layered-to-spinel transitions during cycling as confirmed by dQ/dV, EIS, TEM, and XPS measurements. The obtained LiF/LixPFyOz-coated Li-rich cathode (sample LFP4) delivers an enhanced reversible discharge capacity of 210.7 mA h g−1 at 100 mA g−1 with 90.7% capacity retention after 100 cycles, while the uncoated sample LFP0 suffers from a rapid capacity fading and the capacity retention ratio is only 75.3%. Even at a higher current density of 1000 mA g−1, the discharge capacity of LiF/LixPFyOz-coated sample LFP4 is still as high as 188 mA h g−1 with a capacity retention ratio of 91.2% (much higher than 55.7% for uncoated sample LFP0) after 100 cycles, showing improved cycling stability and superior rate capability. This work demonstrates that LiF/LixPFyOz coating through the LiPF6-electrolyte-solvothermal route is a successful strategy for the modification of Li-rich oxide electrodes for the next-generation of high-energy Li-ion batteries.

Microwave annealing (MWA) and furnace annealing are compared for their low thermal budget capability to improve the characteristics of ZnO-based thin-film transistors (TFTs). Both the ZnO channel and the Al2O3 gate dielectric are fabricated using atomic layer deposition. Using Si-wafer-susceptor assisted MWA with a substantial reduction of both annealing temperature and duration, significant improvements of the characteristics of the ZnO TFTs can be attained. A multi-step MWA process is found to further improve the characteristics of the TFTs. For the same microwave power and total duration, the field-effect mobility of the multi-step MWA TFT is 42% greater than that of the one-step MWA TFT with a similar sub-threshold swing. The multi-step MWA process can serve the purpose at temperatures as low as 220 °C.

Li-rich cobalt-free oxides, popularly used as a cathode with high capacity in lithium ion battery, always suffer from poor cycling stability between 2.0 and 4.8 V vs Li+/Li, especially when cycled at high temperatures (>50 °C). To overcome this issue, Na+ and Al3+ dual-doped NaxLi1.2-xMn0.6-xAlxNi0.2O2 Li-rich cathode is prepared in this study. It is shown that the side reactions between cathode and electrolyte during cycling are suppressed. The improved cycling performance is observed for all of the doped samples, among which the sample with x = 0.03 exhibits the highest capacity retention of 86.1% after 200 cycles between 2.0 and 4.8 V at 2C (1C = 200 mA g−1) and shows a remarkable cycling stability, even at a high temperature of 55 °C (a capacity retention of 92.2% after 100 cycles). Moreover, the average voltage of the sample with x = 0.03 after 100 cycles at 0.5C remains at 3.11 V with a retention ratio of 86.6%. This work provides a new strategy to develop Li-rich cobalt-free cathodes with excellent cycling stability for lithium ion batteries at high temperatures.

Efficient bifunctional oxygen catalysts are required for practical applications in fuel cells and metal-air batteries due to their core electrode reactions: oxygen reduction (ORR) and oxygen evolution (OER). Rational design of nanostructured metal oxides supported by carbon is urgently required to improve the electrochemical properties of Zn-air batteries. Here it is reported that 1D bimetal (Co,Mn) zeolite-imidazole-framework pyrolysis method is used for the low-cost and easy preparation of Co3O4, Mn3O4 nanoparticles and CNx active sites embedded in 1D carbon nanofibers (Co3O4/Mn3O4/CNx@CNFs). The optimized Co3O4/Mn3O4/CNx@CNFs reveals the excellent ORR performance with the diffusion current of −6.96 mA/cm2, along with excellent electrocatalytic activity towards OER (1.63 V at a current density of 10 mA/cm2), which are better than that previously reported bifunctional catalysts dirved from Co, Mn bimetal-oxides. Besides, we assembled the Co3O4/Mn3O4/CNx@CNFs into the air electrode of the Zn-air battery (and flexible Zn-air battery), indicating that the maximum power density is 265 mW/cm2 (and 191 mW/cm2), the latter power density is better than previously reported MOF-derived bifuctional catalysts. The excellent electrocatalytic performance is attributed to the support of 1D highly conductive CNFs and the synergistic effect of active sites such as Co3O4, Mn3O4 and CNx.

Utilized Zn/Co-based metal-organic framework, we successfully fabricate 1D N-doped porous carbon nanofibers anchoring amorphous and graphite carbon-encapsulated CoS2 nanoparticles, using a facile electrospinning strategy combined with annealing treatment. Remarkably, the composite as superior anode for sodium ion battery is rationally designed, and also exhibit enhanced Na-storage performance. The composite shows a large specific capacity of 876 mAh g−1 at 100 mA g−1 in the initial cycles and an outstanding long-term performance (148 mAh g−1 at a current density of 3.2 A g−1 over 1000 cycles). The improved electrochemical performance is ascribed to the 1D porous carbon nanofibers structure and the amorphous and graphite carbon coating, which can relatively inhibit agglomeration of CoS2 nanoparticles, mitigate the volume of the material changes in the process of circulation and provide stabilized electrical conductivity. This research paves the way for extending the 1D metal sulfides and metal-organic framework composites toward potential applications.

Dopant-segregated source/drain contacts in a p-channel Schottky-barrier metal-oxide semiconductor field-effect transistor (SB-MOSFET) require further hole Schottky barrier height (SBH) regulation toward sub-0.1 eV levels to improve their competitiveness with conventional field-effect transistors. Because of the solubility limits of dopants in silicon, the requirements for effective hole SBH reduction with dopant segregation cannot be satisfied using mono-implantation. In this study, we demonstrate a potential solution for further SBH tuning by implementing the dual implantation of boron (B) and aluminum (Al) in combination with microwave annealing (MWA). By using such a method, not only has the lowest hole SBH ever with 0.07 eV in NiSi/n-Si contacts been realized, but also the annealing duration of MWA was sharply reduced to 60 s. Moreover, we investigated the SBH tuning mechanisms of the dual-implanted diodes with microwave annealing, including the dopant segregation, activation effect, and dual-barrier tuning effect of Al. With the selection of appropriate implantation conditions, the dual implantation of B and Al combined with the MWA technique shows promise for the fabrication of future p-channel SB-MOSFETs with a lower thermal budget.

Mediating the backbone coplanarity and solubility of oligothiophenes, especially the head-to-head (HH) disubstituted bithiophene, to achieve an optically and electronically advantageous building block for organic semiconductor materials is a vital yet challenging task. On the other hand, exploring polymer solar cells (PSCs) processed from nonhalogenated solvents is necessary toward their large-scale applications. In this contribution, we develop a HH-type bithiophene analogue (TIPS-T2) by strategically applying the triisopropylsilylethynyl (TIPS) scaffold as the side chain. TIPS can serve to narrow optical band gaps, lower the highest occupied molecular orbital level, reduce intrachain steric hindrance, and guarantee sufficient solubility of the involving polymers. Upon alternating with difluorobenzotriazole (FTAZ) or benzodithiophene-4,8-dione (BDD) acceptor units, two polymers named PT4Si-FTAZ and PT4Si-BDD are synthesized. Encouragingly, non-fullerene PSCs incorporating PT4Si-FTAZ yield a power conversion efficiency of 6.79% when processed from an environment-friendly solvent of trimethylbenzene because of its promoted backbone planarity, as demonstrated by density functional theory, higher hole mobility, and superior film morphology. The results indicate that TIPS-T2 is a promising building block for constructing photovoltaic polymers, and our findings offer an avenue for the ingenious use of TIPS as functional side chains.

In this work, Eu3+ doped Y2O3 hexagonal prisms were synthesized by a novel two-phase approach, which involves water at the bottom as aqueous phase and oleylamine in the above as oil phase. With this unique reaction system, precursors of hexagonal prisms Y4O(OH)9(NO3) were first obtained by simply varying the volume ratio of water to oleylamine. Time-dependent experiments were systematically performed to reveal the growth mechanism of the precursor. After subsequent heat treatment, these precursors transformed to Y2O3 hexagonal prisms with controlled diameters and aspect ratios varying from 4 to 19. Such a transformation is preceded via a topotactic process, as indicated by TG-DTA and mass spectra. Eventually, all Eu3+ doped Y2O3 hexagonal prisms were found to exhibit an intensive red emission at 611 nm, which corresponds to 5D0→7F2 transition of Eu3+. With varying the aspect ratio of hexagonal prisms and increasing Eu3+ concentration in Y2O3, an optimum external quantum efficiency was achieved.

Developing energy storage equipments that can work at very high charge–discharge rate is crucial, but highly challenging for more efficient use of energy. From the perspective of chemistry, high-rate property of Li-ion batteries can only be achieved by significantly improving the kinetics of lithium ions and electrons in electrode. Here, we for the first time report on a simple method to resolve kinetics problems of ultrafast charging–discharging Li-ion batteries by fabrication of layered LiMO2 (M = Mn, Co, Ni) hexagonal sheet exposing with facets {101}. The synthetic procedure of hexagonal sheets is proceeded via a simple PVP-assisted co-precipitation, which is followed by a heat treatment. All hexagonal sheets LiMnxCoyNizO2 were demonstrated to deliver a superior excellent rate capability and outstanding cycle stability at high current density of 3000 mA g−1 and under a high cutoff voltage of 4.4 V. The discharge capacity for the composition LiMn0.075Co0.775Ni0.15O2 at an ultrahigh charge–discharge rate of 10,000 mA g−1 is almost as large as that for LiMn2O4 and commercial LiFePO4 at low rate of 1C. The methodology reported here to resolve the kinetic problems of lithium ions and electrons in electrodes may have many implications that would help scientists to find more high-rate lithium-ion batteries for powering electric vehicles and other applications.

Lithium-ion batteries always suffer from serious capability decay, especially when stored at high temperature and/or for prolonged duration. In this work, electrochemical performance for Li-rich layered oxides Li1.20Mn0.54Co0.13Ni0.13O2 was systematically investigated as a function of temperature and duration. Plenty of techniques like SEM, EDS, EIS, ARC, Raman, XRD, and XPS were utilized to characterize the structures, valence states, compositions, particle sizes, and morphologies of the layered oxides with varying temperature and duration. The results reveal that room temperature storage may alter surface kinetics, but hardly influence the electrochemical performance. While in the case of high temperature storage in pristine state, cycling stability is highly dependent on the storage duration. The degradation mechanism at high temperature storage with prolonged duration is demonstrated to be the accumulation of surface species like LiF/LixPFyOz initiated by the strong reactions between LiPF6 electrolyte and electrode. The results reported here may shed light on predicting electrochemical performance by surface analysis and also provide vital hints on enhancing the high-temperature storage stability of Li-rich layered oxides.

Lithium batteries for UPS, portable electronics and electrical vehicles rely on high-energy cathodes. Li-rich manganese-rich oxide (xLi2MnO3·(1 − x)LiMO2, M = transition metals) is one of the few materials that might meet such a requirement, but it suffers from poor energy retention due to serious voltage and/or capacity fade, which challenges its applications. Here we show that this challenge can be addressed by optimizing the interactions between the components Li2MnO3 and LiMO2 in the Li-rich oxide (i.e. stabilizing the layered structure through Li2MnO3 and controlling Li2MnO3 activation through LiMO2). To realize this synergistic effect, a novel Li2MnO3-stabilized Li1.080Mn0.503Ni0.387Co0.030O2 was designed and prepared using a hierarchical carbonate precursor obtained by a solvo/hydro-thermal method. This layered oxide is demonstrated to have a high working voltage of 3.9 V and large specific energy of 805 W h kg−1 at 29 °C as well as impressive energy retention of 92% over 100 cycles. Even when exposed to 55 °C, energy retention is still as high as 85% at 200 mA g−1. The attractive performance is most likely the consequence of the balanced stability and specific energy in the present material, which is promisingly applicable to other Li-rich oxide systems. This work sheds light on harnessing Li2MnO3 activation and furthermore efficient battery design simply through compositional tuning and temperature regulation.

Though microwave annealing appears to be very appealing due to its unique features, lacking an in-depth understanding and accurate model hinder its application in semiconductor processing. In this paper, the physics-based model and accurate calculation for the microwave annealing of silicon are presented. Both thermal effects, including ohmic conduction loss and dielectric polarization loss, and non-thermal effects are thoroughly analyzed. We designed unique experiments to verify the mechanism and extract relevant parameters. We also explicitly illustrate the dynamic interaction processes of the microwave annealing of silicon. This work provides an in-depth understanding that can expedite the application of microwave annealing in semiconductor processing and open the door to implementing microwave annealing for future research and applications.

A well-designed material comprising Co3O4 nanoparticles embedded in one-dimensional porous nitrogen-doped carbon nanofibers (Co3O4@NCNFs) is prepared through electrospinning, immersion in a cobalt-containing zeolitic imidazolate frameworks (ZIF-67/ZIF-8) and follows by calcination and oxidation. The resultant sample displays a high discharge capacity of 332 mAh g−1 after 200 cycles at a current density of 100 mA g−1 and an outstanding long-term performance (181 mAh g−1 at 1 A g−1 over 1000 cycles), which is better than the reported high current density for Co3O4-based materials. The excellent electrochemical performance is attributed to the nanostructure comprising Co3O4 nanoparticles homogeneously embedded in nitrogen-doped carbon nanofibers, which can effectively inhibit the aggregation of Co3O4 nanoparticles, accommodate the volume change during charge and discharge processes and provide high electrical conductivity of the electrode. This work provides a facile method to obtain one-dimensional oxide composites with high electrochemical performance using a new metal-organic framework as the sacrificial template.

Accurate temperature monitoring of the silicon substrate remains to be a key issue for application of novel microwave annealing technology in advanced semiconductor processing. In this paper, a calibration system for temperature monitoring using infrared thermometer pyrometer is designed and temperature accuracy of silicon substrates with various doping concentrations is analyzed. Furthermore, an accurate temperature monitoring scheme for microwave annealing with silicon substrates is presented and successfully testified with the calibration system.

In this work, a novel solvent-driven room-temperature synthesis of BiPO(4):Eu(3+) nanoparticles was presented. By virtue of 11 solvents with different properties and function groups, phase structure and composition of BiPO(4):Eu(3+) can be systematically tailored. Hexagonal phase (HP) of BiPO(4):Eu(3+) was obtained in water and hydrophobic organic solvents such as arenes and cyclohexane, while low-temperature monoclinic phase (LTMP) was prepared in hydrophilic alcohols. In other solvents (i.e., hydrophilic ethers, aldehydes, ketones, and carboxylic acids), a mixture of HP and LTMP was formed, in which the relative content of LTMP gradually increased following the above solvent sequence. It is also found that particle sizes of BiPO(4):Eu(3+) nanoparticles were closely related to the phase structure: HP exhibited a comparatively larger particle size. The phase evolution processes for both polymorphs with varying solvents were investigated in details. Photoluminescence (PL) properties were sensitive to the phase structure and compositions of the final products. With increasing the phase content of LTMP, the lifetimes and quantum yields both increased. The methodology reported here is fundamentally important, which may give a novel insight into the polymorph-controlled synthesis for further optimized materials performance.

There is a rising demand for low temperature polysilicon TFT these years due to the rapidly increasing market of high resolution display panels. In this paper, both low temperature microwave annealing and laser annealing were used to crystallize amorphous silicon film on glass substrate. It is found that both methods had successfully transferred the amorphous silicon into polysilicon according to Raman spectra results. The microwave crystallized polysilicon had smaller grain size and lower tensile stress than the laser crystallized one. After implantation and activation of BF2 and P, sheet resistance values of the BF2-implanted microwave crystallized samples were similar to that of laser crystallized ones. However, for the P implanted samples, the microwave crystallized samples had two to three magnitude higher sheet resistance compared with the laser crystallized ones.

In this work, microwave annealing is explored to tune the Schottky barrier height between NiSi and Si via boron and arsenic dopant segregation using silicide as diffusion source scheme. The microwave annealing is found to be able to obtain equivalent electron and hole Schottky barrier heights at significantly lower temperature (>100 °C) compared with conventional rapid thermal annealing. A plausible interpretation has been further proposed to explain the impact of low temperature microwave annealing on formation of dopant segregated Schottky junctions. The effectiveness of Schottky barrier height tuning below 400 °C by microwave annealing paves the way to form advanced source/drain and contact structures for future ultra-scaled MOSFETs and monolithic 3D sequential integration.

Heating of silicon substrates featuring different resistivity values by microwave annealing is investigated. The absorption of microwave energy for silicon wafers is found to be consistent with ohmic conduction loss theory. The strongest absorption occurs when the resistivity was around 10 Ω·cm. As the carrier concentration and the conductivity of silicon increase with temperature, the absorption of microwave energy also varies during the annealing processes. Furthermore, it is found that the electric field density around the annealed silicon wafer is stronger for higher conductive silicon substrates at fixed microwave power.

Nickel-rich layered metal oxide materials are prospective cathode materials for lithium ion batteries due to the relatively higher capacity and lower cost than LiCoO2. Nevertheless, the disordered arrangement of Li(+)/Ni(2+) in local regions of these materials and its impact on electrochemistry performance are not well understood, especially for LiNi(1-x-y)Co(x)Mn(y)O2 (1-x-y0.5) cathodes, which challenge one's ability in finding more superior cathode materials for advanced lithium-ion batteries. In this work, Ni-Co-Mn-based spherical precursors were first obtained by a solvothermal method through handily utilizing the redox reaction of nitrate and ethanol. Subsequent sintering of the precursors with given amount of lithium source (Li-excess of 5, 10, and 15 mol %) yields LiNi0.7Co0.15Mn0.15O2 microspheres with different extents of Li(+)/Ni(2+) disordering. With the determination of the amounts of Li(+) ions in transition metal layer and Ni(2+) ions in Li layer using structural refinement, the impact of Li(+)/Ni(2+) ions disordering on the crystal structure, valence state of nickel ions, and electrochemical performance were investigated in detailed. It is clearly demonstrated that with increasing the amount of lithium source, lattice parameters (a and c) and interslab space thickness of unit cell decrease, and more Li(+) ions incorporated into the 3a site of transition metal layer which leads to an increase of Ni(3+) content in LiNi0.7Co0.15Mn0.15O2 as confirmed by X-ray photoelectron spectroscopy and a redox titration. Moreover, the electrochemical performance for as-prepared LiNi0.7Co0.15Mn0.15O2 microspheres exhibited a trend of deterioration due to the changes of crystal structure from Li(+)/Ni(2+) mixing. The preparation method and the impacts of Li(+)/Ni(2+) ions disordering reported herein for the nickel-rich layered LiNi0.7Co0.15Mn0.15O2 microspheres may provide hints for obtaining a broad class of nickel-rich layered metal oxide microspheres with superior electrochemical performance.

Li-rich layered oxides have attracted much attention for their potential application as cathode materials in lithium ion batteries, but still suffer from inferior cycling stability and fast voltage decay during cycling. How to eliminate the detrimental spinel growth is highly challenging in this regard. Herein, in situ K(+)-doped Li1.20Mn0.54Co0.13Ni0.13O2 was successfully prepared using a potassium containing α-MnO2 as the starting material. A systematic investigation demonstrates for the first time, that the in situ potassium doping stabilizes the host layered structure by prohibiting the formation of spinel structure during cycling. This is likely due to the fact that potassium ions in the lithium layer could weaken the formation of trivacancies in lithium layer and Mn migration to form spinel structure, and that the large ionic radius of potassium could possibly aggravate steric hindrance for spinel growth. Consequently, the obtained oxides exhibited a superior cycling stability with 85% of initial capacity (315 mA h g(-1)) even after 110 cycles. The results reported in this work are fundamentally important, which could provide a vital hint for inhibiting the undesired layered-spinel intergrowth with alkali ion doping and might be extended to other classes of layered oxides for excellent cycling performance.

Multicomponent spinel metal-oxide assembled mesoporous microspheres, promising anode materials for Li-ion batteries with superior electrochemical performance, are usually obtained using different kinds of precursors followed by high-temperature post-treatments. Nevertheless, high-temperature calcinations often cause primary particles to aggregate and coarsen, which may damage the assembled microsphere architectures, leading to deterioration of electrochemical performance. In this work, binary spinel metal-oxide assembled mesoporous microspheres MnCo2O4 were fabricated by one-step low-temperature solvothermal method through handily utilizing the redox reaction of nitrate and ethanol. This preparation method is calcination-free, and the resulting MnCo2O4 microspheres were surprisingly assembled by nanoparticles and nanosheets. Two kinds of MnCo2O4 crystal nucleus with different exposed facet of (1̅10) and (11̅2̅) could be responsible for the formation of particle-assembled and sheet-assembled microspheres, respectively. Profiting from the self-assembly structure with mesoporous features, MnCo2O4 microspheres delivered a high reversible capacity up to 722 mAh/g after 25 cycles at a current density of 200 mA/g and capacities up to 553 and 320 mAh/g after 200 cycles at a higher current density of 400 and 900 mA/g, respectively. Even at an extremely high current density of 2700 mA/g, the electrode still delivered a capacity of 403 mAh/g after cycling with the stepwise increase of current densities. The preparation method reported herein may provide hints for obtaining various advanced multicomponent spinel metal-oxide assembled microspheres such as CoMn2O4, ZnMn2O4, ZnCo2O4, and so on, for high-performance energy storage and conversion devices.

Metal oxide nanomaterials have been found to have great potential for diverse applications due to their unique relationships between structure and properties. Lattice expansion as particle size reduces was previously considered to be general for metal oxide nanomaterials. It is now a great challenge to see if lattice contraction could be induced by the size effect for metal oxide nanomaterials. ABO4 metal oxides (e.g., CaWO4, GdVO4, and CdWO4) are some of the most important functional materials with many applications, while such oxides at the nanoscale are never reported to show a lattice contraction. This work presents a first report on the variation from lattice expansion to lattice contraction by tuning the microstructures of GdVO4:Eu(3+) nanocrystals. A hydrothermal method was adopted to synthesize GdVO4:Eu(3+) nanocrystals, and then these nanoparticles were calcined at 600 ° C in air. It is found that particle size reduction led to a lattice contraction for the calcined samples, which is in contrast to the lattice expansion observed for the hydrothermally synthesized counterparts or many other metal oxide nanomaterials. In addition, the lattice symmetry of the calcined samples remained almost a constant. The results indicate that the negative surface stress was eliminated by calcination treatment, leading to a homogeneous compression process in the lattice structure of the calcined GdVO4:Eu(3+) nanocrystals. Furthermore, Eu(3+) was taken as a structural probe and a luminescence center to study the local environments pertinent to these structural changes and to optimize the photoluminescence performance.

The Schottky junction source/drain structure has great potential to replace the traditional p/n junction source/drain structure of the future ultra-scaled metal-oxide-semiconductor field effect transistors (MOSFETs), as it can form ultimately shallow junctions. However, the effective Schottky barrier height (SBH) of the Schottky junction needs to be tuned to be lower than 100 meV in order to obtain a high driving current. In this paper, microwave annealing is employed to modify the effective SBH of NiSi on Si via boron or arsenic dopant segregation. The barrier height decreased from 0.4–0.7 eV to 0.2–0.1 eV for both conduction polarities by annealing below 400 °C. Compared with the required temperature in traditional rapid thermal annealing, the temperature demanded in microwave annealing is ~60 °C lower, and the mechanisms of this observation are briefly discussed. Microwave annealing is hence of high interest to future semiconductor processing owing to its unique capability of forming the metal/semiconductor contact at a remarkably lower temperature.

The title nanoparticles are synthesized at room temperature from mixtures of Bi(NO3)3 and Eu(NO3)3 dissolved in various solvents by precipitation with NH4H2PO4.

Li-rich layered materials are considered to be the promising low-cost cathodes for lithium-ion batteries but they suffer from poor rate capability despite of efforts toward surface coating or foreign dopings. Here, spinel-layered Li-rich Li-Mn-Co-O microspheres are reported as a new high-rate cathode material for Li-ion batteries. The synthetic procedure is relatively simple, involving the formation of uniform carbonate precursor under solvothermal conditions and its subsequent transformation to an assembled microsphere that integrates a spinel-like component with a layered component by a heat treatment. When calcined at 700 °C, the amount of transition metal Mn and Co in the Li-Mn-Co-O microspheres maintained is similar to at 800 °C, while the structures of constituent particles partially transform from 2D to 3D channels. As a consequence, when tested as a cathode for lithium-ion batteries, the spinel-layered Li-rich Li-Mn-Co-O microspheres obtained at 700 °C show a maximum discharge capacity of 185.1 mA h g−1 at a very high current density of 1200 mA g−1 between 2.0 and 4.6 V. Such a capacity is among the highest reported to date at high charge-discharge rates. Therefore, the present spinel-layered Li-rich Li-Mn-Co-O microspheres represent an attractive alternative to high-rate electrode materials for lithium-ion batteries.

Microwave annealing is shown to be viable for achieving low thermal budget formation of ultra-shallow junctions. Regrowth of a 10 nm thick amorphous Si layer that is generated during a Ge amorphization process prior to BF2 or As dopant implantation proceeds at rates up to 0.53 nm/min for BF2 and up to 0.33 nm/min for As at 370 °C. The fraction of electrical activation for implanted dopants is as high as 13% for BF2 and 32% for As with negligible diffusion at 540 °C.

We initiated a self-adjusted oxygen-partial-pressure approach to prepare high-performance Li2MnO3–LiMO2 cathode material. Four different lithium resources, lithium acetate, lithium hydrate, lithium carbonate, and lithium nitrate were used to create the local oxygen partial pressure over the samples. Since the melting points or decomposition temperatures for these lithium resources decrease in a sequence, Li2CO3 ≈ LiOH > LiNO3 > CH3COOLi, the oxygen partial pressure of the four crucibles that contain these lithium salts increases in a sequence, S4 ≈ S3 < S2 < S1 ≈ air in muffle furnace (S1: CH3COOLi·2H2O, S2: LiNO3, S3: LiOH·H2O, and S4: Li2CO3). Regardless of the lithium resources, the decomposed gases reduced the local oxygen partial pressures, leading to an incomplete oxidation of Mn ions in the final product Li[Li0.14Mn0.47Ni0.25Co0.14]O2. That is, some of the Mn3+ ions existed in the final product Li[Li0.14Mn0.47Ni0.25Co0.14]O2, and the amount of Mn3+ ions was closely related to the oxygen partial pressure. The lower oxygen partial pressure gave rise to a larger amount of Mn3+ in the final products, as confirmed by X-ray photoelectron spectroscopy. Electrochemical tests showed that the products prepared using lithium carbonate exhibited the best electrochemical performance: the initial discharge capacity was 279.4 mA h g−1 at a current density of 20 mA g−1, which remained as high as 187.2 mA h g−1 even at a much higher current density of 500 mA g−1. Such excellent electrochemical performance could be ascribed to the presence of Mn3+ that decreased the surface layer resistance and charge transfer resistance, and that further increased the conductivity and Li+ ion diffusion coefficient.