Transmission Spectral Characteristics of Photonic Crystals Milled in Annealed Proton-Exchange LiNbO_3 Waveguide

Transmission spectra of triangular lattice photonic crystals milled in the top surface of an annealed proton- exchange waveguide are numerically simulated. The effects of the finite depth, conical shape, trapezoidal shape and hybrid shape of holes are theoretically analyzed. Due to the difficulty of milling high aspect-ratio cylindrical holes in lithium niobate （LiNbO3 ）, a compromised solution is proposed to improve the overlap between shallow holes and the waveguide mode, and useful transmission spectra with strong contrast and sharp band edges are achieved.

XPS Studies on Electroless As-Deposited and Annealed Ni-P Films

Electroless deposition has been used to deposit Ni-P films on glass slides using the reducing agent sodium hypophosphite. This has been done with a purpose to use Ni-P films as back contact for silicon carbide radiation detectors. By keeping deposition time, temperature, pH and concentration of the precursor solution constant, the film deposition has been done. XPS studies were done to analyze the composition and stoichiometry of Ni-P thin films.

Effects of stoichiometric ratio La/Mg on structures and electrochemical performances of as-cast and annealed La-Mg-Ni-based A_2B_7-type electrode alloys

In order to investigate the influences of the stoichiometric ratio of La/Mg （increasing La and decreasing Mg on the same mole ratio） on the structure and electrochemical performances of the La-Mg-Ni-based A2B7-type electrode alloy, the as-cast and the annealed ternary Lao.8＋xMgo.2_xNi3.5 （x=0-0.05） electrode alloys were prepared. The characterization of electrode alloys by X-ray diffraction （XRD） and scanning electron microscopy （SEM） shows that all the as-cast and the annealed alloys hold two major phases of （La,Mg）2Ni7 and LaNi5 as well as a residual phase of LaNi3. Moreover, the increase of La/Mg ratio brings on a decline of （La,Mg）2Ni7 phase and a rise of LaNi5 and LaNi3 phases. The variation of La/Mg ratio gives rise to an evident change of the electrochemical performances of the alloys. The discharge capacities of the as-cast and the annealed alloys evidently decrease with growing the La/Mg ratio, while the cycle stabilities of the alloys visibly augment under the same condition. Furthermore, the high rate discharge ability （HRD）, the electrochemical impedance spectrum （EIS）, the Tafel polarization curves, and the potential step measurements all indicate that the electrochemical kinetic properties of the alloy electrodes increase with the La/Mg ratio rising.

Electrical Transport Properties of Annealed Undoped InP

The electrical properties of annealed undoped n type InP are studied by temperature dependent Hall effect (TDH) and current voltage ( I V ) measurements for semiconducting and semi insulating samples,respectively.Defect band conduction in annealed semiconducting InP can be observed from TDH measurement,which is similar to those of as grown unintentionally doped InP with low carrier concentration and moderate compensation.The I V curves of annealed undoped SI InP exhibit ohmic property in the applied field region up to the onset of breakdown.Such a result is different from that of as grown Fe doped SI InP which has a nonlinear region in I V curve explained by the theory of space charge limited current.

Preparation and Characterization of Electrodeposited-Annealed CulnSe2 Thin Films for Solar Cells

CuInSe2 （CIS） films with good crystalline quality were synthesized by electrodeposition followed by annealing in Se vapor at 530 ℃. The morphology, composition, crystal structure, optical and electrical properties of the CIS films were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-VISNIR spectroscopy, and admittance spectroscopy. The results revealed that the annealed CIS films had chalcopyrite structure and consisted of relatively large grains in the range of 500-1000 nm and single grain of films extend usually through the whole film thickness. The band gap of CIS films was 0.98 eV and carrier concentration was in the order of 1016 cm-3 after etching the Cu-Se compounds on the film surface. Solar cells with the structure of AZO/i-ZnO/CdS/CIS/Mo/glass were fabricated. Current density vs. voltage test under standard reported condition showed the solar cells with an area of 0.2 cm2 had a conversion efficiency of 0.96%. The underlying physics was also discussed.

Giant Magneto-Impedance Effect in Amorphous and Current Annealed Fe73.5Cu1Nb3Si13.5B9 Wire

The magneto-impedance(MI) effect in amorphous and current annealed Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 wires has been measured to investigate the influence of DC annealing,highcurrent-density electropulsing annealing and tensile stress applied during annealing process.The results showed that the MI of DC annealed sample exhibits a sharp maximum.The Maximum MI ratio of 60%was observed in the sample of high-current-density electropulsing annealed under applied tensile stress.

FERROELECTRIC CHARACTERISTICS OF SrBi_2Ta_2O_9 THIN FILMS ANNEALED IN FORMING GAS

The degradation behavior of SrBi2Ta2O9 (SBT) thin films annealed in forming gas (5%H2+95%N2) was investigated. The ferroelectric remnant polarization Px of SBT had a severe decrease in the containing H2 atmosphere at 400°C. SEM results showed that Bi could be reduced from SBT thin films for the effect of H2. The reduction role increased with a rise of annealing temperature. SBT thin films lost their ferroelectricity when the annealing temperature was above 450°C. It implied that the degradation of Pr value or the disappearance of ferroelectricity in SBT thin, films had the relationship with the reductive amounts of Bi in SBT. H2 played an important role in degradation of ferroelectric SBT thin films. This role could be attributed to its strong reduction activity during forming gas annealing.

Effect of Processing Condition on Texture and Drawability of a Ferritic Rolled and Annealed Interstitial-Free Steel

The processing conditions of the texture formation and deep drawability of a Ti-IF steel strip hot-rolled in ferritic region and subsequently annealed were investigated. The r-value increases with the decrease of reheating temperature, and finish rolling temperature and the increase of reductions in ferritic region. For lubricated ferritic rolling and annealing, the r-value is raised up to 1.75, and elongation rate is over 50% at the finish rolling temperature of 650 ℃, which is suitable for DDQ grade products. However, the r-value is below 1.0 in the case of unlubricated rolling. The X-ray diffraction was used to analyze the textural characteristic of samples. For samples subjected to lubricated rolling and annealing, the strong { 111 }//ND recrystallization texture is distributed homogeneously along the thickness direction, and the intensity of { 110} recrystallization texture is very low even in surface. However, for unlubricated samples, the {111} texture is distributed inhomogeneously and is weak along the thickness direction, and （110}//ND recrystallization texture is strong, which deteriorates the formability.

Adsorption and desorption phenomena on thermally annealed multi-walled carbon nanotubes by XANES study

The multi-walled carbon nanotubes(MWCNTs) studied in this work were synthesized by the catalytic chemical vapor deposition(CCVD) process, and were thermally annealed by the hot filament plasma enhanced(HF PE) method at 550℃ for two hours.The x-ray absorption near edge structure(XANES) technique was used to investigate the adsorption and desorption phenomena of the MWCNTs at normal and grazing incidence angles.The adsorbates were found to have different sensitivities to the thermal annealing.The geometry of the incident beam consistently gave information about the adsorption and desorption phenomena.In addition, the adsorption of non-intrinsic potassium quantitatively affected the intrinsic adsorbates and contributed to increase the conductivity of the MWCNTs.The desorption of potassium was almost 70% greater after the thermal annealing.The potassium non-intrinsic adsorbates are from a physisorption mechanism whereas the intrinsic adsorbates result from chemisorption.

Effect of Fast Cooling Rate on the Microstructure and Mechanical Properties of Low-Carbon High-Strength Steel Annealed in the Intercritical Region

The effect of fast cooling rate on the microstructure and mechanical properties of low-carbon high-strength steel annealed in the intercritical region was investigated using a Gleeble 1500 thermomechanical simulator and a continuous annealing thermomeehanical simulator. The results showed that the microstructure consisted of ferrite and bainite as the main phases with a small amount of retained austenite and martensite islands at cooling rate of 5 and 50 ℃/s, respectively. Fast cooling after continuous annealing affected all constituents of the microstructure. The mechanical properties were improved considerably. Ultimate tensile strength （U-TS） increased and total elongation （TEL） decreased with increasing cooling rate in all specimens. The specimen 1 at a cooling rate of 5 ℃/s exhibited the maximum TEL and UTSxTEL （20% and 27 200 MPa%, respectively） because of the competition between weakening by presence of the retained austenite plus the carbon indigence by carbide precipitation, and strengthening by martensitic islands and precipitation. The maximum UTS and YS （1 450 and 951 MPa, respectively） were obtained for specimen 2 at a cooling rate of 50 ℃/s. This is attributed to the effect of dispersion strengthening of finer martensite islands and the effect of precipitation strengthening of carbide precipitates.

Thermally annealed gamma irradiated Ni/4H-SiC Schottky barrier diode characteristics

Thermal annealing effects on gamma irradiated Ni/4 H-SiC Schottky barrier diode(SBD) characteristics are analyzed over a wide range of temperatures(400–1100 °C). The annealing induced variations in the concentration of deep level traps in the SBDs are identified by thermally stimulated capacitance(TSCAP). A little decrease in the trap density at E_C – 0.63 eV and E_C –1.13 eV is observed up to the annealing temperature of 600 °C. Whereas, a gamma induced trap at E_C – 0.89 eV disappeared after annealing at 500 °C, revealing that its concentration(< 1013 cm-3) is reduced below the detection limit of the TSCAP technique.The electrical characteristics of irradiated SBDs are considerably changed at each annealing temperature. To understand the anomalous variations in the post-annealing characteristics, the interface state density distribution in the annealed SBDs is extracted.The electrical properties are improved at 400 °C due to the reduction in the interface trap density. However, from 500 °C, the electrical parameters are found to degrade with the annealing temperature because of the increase in the interface trap density.From the results, it is noted that the rectifying nature of the SBDs vanishes at or above 800 °C.

Primary Recrystallization of Grain Oriented Silicon Steel Strip Rolled by CSR and Annealed in Magnetic Field

The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling （CSR） of different mismatched speed ratio （MSR） and annealed in magnetic field under hydrogen were presented.Effects of the factors such as thickness and mismatched speed ratio on the magnetic properties and recrystallization texture were analyzed and the recrystallization principles in magnetic field annealing were discussed. The study would provide a new route for mass production of high quality ultra-thin grain oriented silicon steel strip.

Influence of carrier gas H2 flow rate on quality of p-type GaN epilayer grown and annealed at lower temperatures

In this work, we study the influence of carrier gas H2flow rate on the quality of p-type GaN grown and annealed at lower temperatures. It is found that the concentration of H atoms in Mg-doped GaN epilayer can effectively decrease with appropriately reducing the carrier gas H2flow rate, and a high-quality p-type GaN layer could be obtained at a comparatively low annealing temperature by reducing the carrier gas H2flow rate. Meanwhile, it is found that the intensity and wavelength of DAP peak are changed as the annealing temperature varies, which shows that the thermal annealing has a remarkable effect not only on the activation of acceptors but also on the compensation donors.

Behaviour of Charge Carriers in As-Deposited and Annealed Undoped TCO Films

We examine the structures,cut-off points of transmittance spectra and electric properties of undoped ZnO,SnO_(2) and CdO films by scanning electron microscopy,x-ray diffraction,spectrophotometer and Hall-effect measurements,respectively.The films are deposited by using an rf magnetron sputtering system from powder targets in argon and then annealed in vacuum.The structures and properties of the as-deposited films are compared with those of the annealed one.We try to explain the behaviour of charge carriers based on the semiconductor physics theory.

MICROSTRUCTURE AND PROPERTIES OF ANNEALED ZnO THIN FILMS DEPOSITED BY MAGNETRON SPUTTERING

ZnO thin films were deposited on a glass substrate by dc (direct current) and rf (radio frequency) magnetron sputtering. Post-deposition annealing was performed in different atmospheres and at different temperatures. The correlation of the annealing conditions with the microstructure and properties of the ZnO films wer e investigated by ultraviolet-visible spectroscopy, X-ray diffraction, conductiv ity measurement and scanning electron microscopy. Only the strong 002 peak could be observed by X-ray diffraction. The post-deposition annealing of ZnO films wa s found to alter the film's microstructure and properties, including crystallini ty, porosity, grain size, internal stress level and resistivity. It was also fou nd that after annealing, the conductivity of poorly conductive samples often imp roved. However, annealing does not improve the conductivity of samples with high conductivity prior to annealing. The resistivity of as-grown films can be decre ased from 102 to 10-4Ω·cm after annealing in nitrogen. To explain the effects of annealing on the conductivity of ZnO, it is believed that annealing may alter the presence and distribution of oxygen defects, reduce the lattice stress, cau se diffusion, grain coarsening and recrystallization. Annealing will reduce the density of grain boundaries in less dense films, which may decrease the resistiv ity of the films. On the other hand, annealing may also increase the porosity of thin films, leading to an increase in resistivity.

Comparative study of electrical characteristics for n-type 4H–SiC planar and trench MOS capacitors annealed in ambient NO

The interface properties and electrical characteristics of the n-type 4H-SiC planar and trench metal-oxide-semiconductor （MOS） capacitors are investigated by measuring the capacitance voltage and current voltage. The flat-band voltage and interface state density are evaluated by the quasi-static method. It is not effective on further improving the interface properties annealing at 1250 ℃ in NO ambient for above 1 h due to the increasing interface shallow and fast states. These shallow states reduce the effective positive fixed charge density in the oxide. For the vertical MOS capacitors on the （1120） and （1100） faces, the interface state density can be reduced by approximately one order of magnitude, in comparison to the result of the planar MOS capacitors on the （0001） face under the same NO annealing condition. In addition, it is found that Fowler-Nordheim tunneling current occurs at an oxide electric field of 7 MV/cm for the planar MOS device. However, Poole-Frenkel conduction current occurs at a lower electric field of 4 MV/cm for the trench MOS capacitor. This is due to the local field crowded at the trench corner severely causing the electrons to be early captured at or emitted from the SiO2/SiC interface. These results provide a reference for an in-depth understanding of the mobility-limiting factors and long term reliability of the trench and planar SiO2/SiC interfaces.

Four-inch high quality crack-free AlN layer grown on a hightemperature annealed AlN template by MOCVD

In this work,based on physical vapor deposition and high-temperature annealing(HTA),the 4-inch crack-free high-quality AlN template is initialized.Benefiting from the crystal recrystallization during the HTA process,the FWHMs of X-ray rocking curves for(002)and(102)planes are encouragingly decreased to 62 and 282 arcsec,respectively.On such an AlN template,an ultra-thin AlN with a thickness of~700 nm grown by MOCVD shows good quality,thus avoiding the epitaxial lateral over-growth(ELOG)process in which 3-4μm AlN is essential to obtain the flat surface and high crystalline quality.The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED,therefore significantly improving yields and decreasing cost.

An investigation on electrochemical performances of as-cast and annealed La_(0.8)Mg_(0.2)Ni_(3.3)Co_(0.2)Si_x(x=0-0.2)alloy electrodes for Ni/MH battery application

The La-Mg-Ni-based A2B7-type La0.5Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The influences of the additional silicon and the annealing treatment on the structure and electrochemical performances of the alloys were investigated systemically. Both of the analyses of XRD and SEM reveal that the as-cast and annealed alloys are of a multiphase structure, involving two main phases （La, Mg）2Ni7 and LaNi5 as well as one minor phase LaNi3. The addition of Si and annealing treatment bring on an evident change in the phase abundances and cell parameters of （La, Mg）2Ni7 and LaNi5 phase for the alloy without altering its phase structure. The phase abundances decrease from 74.3% （x=0） to 57.8% （x=0.2） for the （La, Mg）2Ni7 phase, and those of LaNi5 phase increase from 20.2% （x^0） to 37.3% （x=0.2）. As for the electrochemical measurements, adding Si and performing annealing treatment have engendered obvious impacts. The cycle stability of the alloys is improved dramatically, being enhanced from 80.3% to 93.7% for the as-annealed （950 ℃） alloys with Si content increasing from 0 to 0.2. However, the discharge capacity is reduced by adding Si, from 399.4 to 345.3 mA.h/g as the Si content increases from 0 to 0.2. Furthermore, such addition makes the electrochemical kinetic properties of the alloy electrodes first increase and then decrease. Also, it is found that the overall electrochemical properties of the alloys first augment and then fall with the annealing temperature rising.

Anisotropic tensile behavior and related yield point phenomena in annealed ultrafine-grained pure aluminum

It is found that tensile flow curves of samples of annealed ultrafine-grained aluminum AA1090 show the development of a yield point and a significant mechanical anisotropy.To rationalize the anisotropic tensile behavior,the orientation data of the annealed material were measured using electron backscatter microscopy.It is found that the inferior mechanical properties of samples tested at 45°to the rolling direction may be attributed to a strong rolling texture effect and that the anisotropic magnitude of the yield drop may be related to the proportion of grains with soft orientations(defined as those with Schmid factor greater than 0.45)in the sample.Additionally,it is found that the anisotropy in tensile ductility is in general agreement with a Considère criterion analysis and that the mechanical anisotropy in the samples is only partly explained by the crystallographic texture,where microstructural anisotropy may also play a role.

Room Temperature Visible Photoluminescence from Thermally Annealed Hydrogenated Amorphous Silicon Films

A visible photoluminescence from a thermally annealed boron doped hydrogenated amorphous silicon(a-Si:H)film has been observed at room temperature.The wavelength at the peak of the photoluminescent spectra is about 600nm.The intensity of photoluminescence is dependent on the annealing temperature strongly and relative to the deposition technology parameters of the films,especially to the hydrogen dilution of the boron doped silane and the deposition rate of the films.There exists a quantum size effect of nanometer-scale porosity on the surface of the annealed a-Si:H film.The quantum-confined structures may form due to the evolution of hydrogen from the surface of the films during the annealing procedure.The density of the porosity is relative to the quantity of evolved hydrogen from the film and the evolution rate of the hydrogen.