INFLUENCE OF SUBSTRATE TEMPERATURE ON THE STRUCTURE OF SPUTTERED a-Si_(1-x)Sn_(x):H ALLOYS

X-ray diffraction, SEM and XPS were used to detect the structure of sputtered a-Si_(1-x)Sn_(x):H alloys. It is verified that the types of Sn site in the alloys depend on substrate temperature Ts. Most of the Sn atoms are substituted for Si at Ts 220℃, whereas a larger fraction of β-Sn clusters are formed at Ts 220℃.

Facile synthesis of NiMn2S4 nanoflakes on nickel foam for high-performance aqueous asymmetric supercapacitors

Supercapacitors display promising electrochemical performance with high power density and excellent cycle stability.However,their low energy density limits their advancement in a broader range of applications.To enhance their energy density,we proposed self-assembled spinel NiMn2S4nanoflakes grown on nickel foam which we successfully prepared by a facile hydrothermal method.The NiMn2S4electrode delivers a high capacitance of 2096.7 F g^(-1)at 1.0 A g^(-1),with an exceptional rate capability(~720.6 F g^(-1)at a very high current density of 100 A g^(-1))and good cycle stability(~85.1%retention of the initial capacitance after 7000 cycles with the Coulombic efficiency around 100%).The as-fabricated asymmetric supercapacitors based on NiMn2S4nanoflakes//active carbon demonstrate an energy density of 73.6 W h kg^(-1)at 800.5 W kg^(-1)and adequate cycling performance of~84.6%capacitance retention at 15 A g^(-1)after 10000 cycles.The results reveal that the nanostructured NiMn2S4is an excellent electrode material for high-performance energy storage applications.

Preparation and electrochemical performance of MWCNTs@MnO_2 nanocomposite for lithium ion batteries

Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-discharge tests were used to characterize the structures and electrochemical performances of the as-prepared nanocomposite.The capacity reaches 1233.6 mA h g-1 at a current density of 100 mA g-1 for the first discharge,and it can still maintain a capacity of 633.1mA h g-1 after 100 charge-discharge cycles.The results show that MWCNTs with good electrical conductivity as anchors of MnO2 can provide fast electron transport channels for MnO2 in the electrochemical reactions,and the as-prepared MWCNTs@MnO2 nanocomposite is a potential anode material for lithium ion batteries.

High-performance aqueous asymmetric supercapacitors based on the cathode of one-step electrodeposited cracked bark-shaped nickel manganese sulfides on activated carbon cloth

In this work,we report a high-performance self-standing supercapacitor electrode of mixed nickel manganese sulfides (NMSs)with a cracked-bark shape grown by one-step electrochemical deposition on activated carbon cloth (ACC).The electrode possesses outstanding electrochemical properties,including a high specific capacitance of up to 3142.8 F g^(-1)at 1.0 A g^(-1),the high-rate performance (~1206.8 F g^(-1)at 60.0 A g^(-1)),and cycle stability (~92.3%capacitance retention after 8000 cycles at8 A g^(-1)).An asymmetric supercapacitor assembled using NMSs on ACC as the cathode,activated carbon on carbon cloth as the anode and 1.0 mol L;KOH as the electrolyte delivers a high energy density of 111.2 W h kg^(-1)at 800.0 W kg^(-1)and the prominent cycling performance of~93.2%capacitance retention after 10000 cycles at 5 A g^(-1)with the Columbic efficiency of around 100%during these 10000 cycles.The high performance and facile preparation indicate that the NMSs on ACC hold a huge potential as the electrode for supercapacitors.

Kinetic Monte Carlo simulation of film morphologies at the initial stages

The morphologies at the initial stages of thin film growth were studied by using Kinetic Monte Carlo techniques.A more efficient model was used to calculate the activity energy.The model involves incident atom attachment,diffusion,detachment from the surface,detached atom returning,and dimer diffusion.We edited a set of software of the model and simulated the surface morphologies by the principle of computer graphics.It is shown that the nucleuses formed at the initial stages and the surface morphologies at high temperatures are very different from those at low temperatures.The later surface growth depends on the nucleuses at the initial stages.The mechanism results from the atom thermal movement,the temperature determines the diffusion ability,and the deposition rate determines the diffusion time.

Study on performance of PVDF piezoelectric film for the separator in Li-ion rechargeable cell

The properties of piezoelectric PVDF films as separators are studied in NiO/Li electrodes Li-ion power cell.The results show that the PVDF piezoelectric film with excellent insulation is suitable for the environmental energy harvesting application.This is attributable to the compact structure of the piezoelectric PVDF film,and which make it has low leakage current and low charge-discharge current characteristics.

Annealing effects on the photoluminescence of Pb-ion irradiated He-doped sapphire

In the present work, the photoluminescence （PL） character of single crystal sapphire （A1203） samples with and without im- plantation by 110 keV He and/or irradiation by 230-MeV Pb ions, as well as subsequently annealing at 600, 900 and 1100 K （TA） was studied. The modification of the structure and optical properties induced by ion irradiation were analyzed by using PL and FTIR spectra. The PL measurements showed that luminescence peaks located at 390, 413,450, and 564 nm appeared in irradiated samples. The luminescence peaks appeared at 360, 380, and 516 nm after annealing. Infrared spectra showed a broad- ening of the absorption band between 460 cm^-1 and 510 cm^-1, which indicated the formation of strongly damaged regions in the Al2O3 samples. The position shift of the absorption band in 1000-1300 cm^-1 tended towards to a higher wavelength.

Field electron emission of diamond films on nanocrystalline diamond coating by CVD method

The preparation process, structure feature and field electron emission characteristic of diamond films on nanocyrstalline diamond coating by the CVD method were studied. The field electron emission measurements on the samples showed that the diamond films have lower turn-on voltage and higher field emission current density. A further detailed theory explanation to the results was given.

Electron field emission from nano-crystalline Si films deposited by inductively coupled plasma CVD at room temperature

硅薄电影被诱导地联合的血浆 CVD 在房间温度扔。拉曼光谱和原子力量显微镜学被用来描绘样品的结构和地形学。在最佳血浆条件下面， nano-crystallineSi 电影与在表面上的随机的分布的高密度的 Si 尖端是成年的，这被显示出。高度和 Si 尖端的吝啬的基础直径分别地是 30-40 nm 和约 200 nm。有如此的表面地形学的电影被表明有电子领域排放的好行为。典型阀值地关于 7-10 V/mu m。