Effects Of Nitrogen Annealing Research Articles

The Effect of Nitrogen Annealing on the Resistive Switching Characteristics of the W/TiO2/FTO Memory Device

In this paper, the effect of nitrogen annealing on the resistive switching characteristics of the rutile TiO2 nanowire-based W/TiO2/FTO memory device is analyzed. The W/TiO2/FTO memory device exhibits a nonvolatile bipolar resistive switching behavior with a high resistance ratio (RHRS/RLRS) of about two orders of magnitude. The conduction behaviors of the W/TiO2/FTO memory device are attributed to the Ohmic conduction mechanism and the Schottky emission in the low resistance state and the high resistance state, respectively. Furthermore, the RHRS/RLRS of the W/TiO2/FTO memory device is obviously increased from about two orders of magnitude to three orders of magnitude after the rapid nitrogen annealing treatment. In addition, the change in the W/TiO2 Schottky barrier depletion layer thickness and barrier height modified by the oxygen vacancies at the W/TiO2 interface is suggested to be responsible for the resistive switching characteristics of the W/TiO2/FTO memory device. This work demonstrates the potential applications of the rutile TiO2 nanowire-based W/TiO2/FTO memory device for high-density data storage in nonvolatile memory devices.

Re-Investigation of SiC/SiO<sub>2</sub> Interface Passivation by Nitrogen Annealing

Effect of nitrogen annealing on SiC/SiO2 interface properties was comparatively investigated for SiC MOS capacitors. Interface properties were characterized by normalized parallel conductance and interface state density value, and dielectric strength was evaluated by the electric-field-to-breakdown (Ebd). The results exhibited that both fast and slow states were present at the nitrogen-annealed samples’ parallel conductance characteristics. Thus, we could conclude that nitrogen annealing led to incomplete nitridation of SiC/SiO2 interface. Based on the results, nitridation mechanism was simply analyzed. It seemed that the nitridation process started from near conduction band, extending till to mid-band-gap. Besides, when the samples underwent higher temperature nitrogen annealing, more slow states were converted into fast ones, indicating that higher annealing temperature could lead to more effective nitridation. It was suggested that nitrogen annealing resulted in incomplete nitridation of SiC/SiO2 interface regardless of oxide thickness and that this process was limited to the annealing temperature. The higher the annealing temperature was, the more effective the nitridation effects were.

The effect of nitrogen annealing on lithium ion intercalation in nickel-doped lithium trivanadate

The communication reports an exploratory experimental study on the effects of nitrogen annealing on lithium ion intercalation in nickel-doped lithium trivanadate cathodic electrodes for lithium ion batteries. It shows good rate performance with discharge capacities of 348.6, 252.6, 191.9 and 96.7mAh g−1 at 0.2, 0.5, 1 and 5 C, respectively. Nitrogen annealing resulted in the formation of parasitic secondary-phase LiV2O5 and appreciably increased tetravalent vanadium ions compensated with oxygen vacancies, which would enhance the electronic conductivity and lithium ion diffusivity and promote the interface interaction and deintercalation process, and thus lead to the enhanced lithium ion intercalation properties. The possible impacts of the parasitic secondary-phase LiV2O5 on the lithium ion intercalation performance have also been discussed.

Effect of nitrogen annealing on the structural, optical and photoluminescence properties of In2O3 thin films

The effect of heat treatment under nitrogen atmosphere on the structural, optical and photoluminescence properties of In2O3 thin films was studied in this work. In2O3 thin layers were annealed at 250 and 450 °C during 1 and 2 h. All heated films are polycrystalline and crystallize in to the body centered cubic structure with (400) as preferred orientation. Optical properties reveal an enhancement of transmission T in the transparency zone for 250 °C during 2 h and 450 °C during 1 h (T is of about 75%). Transmission and reflection spectra of the films exhibit interferences fringes which is characteristics of thickness uniformity and surface homogeneity. The heated films show a large band gap energy Eg varying from 3.41 to 3.49 eV. The refractive index was investigated using the envelope method. The extinction coefficient k, dielectric constant εr, packing density p and porosity were also studied using the refractive index results. The single oscillator energy E0 and dispersion energy Ed were determined using Wemple oscillatory model based on the envelope method. The obtained results lead to conclude that annealed In2O3 thin films is a good candidate to be used in many optoelectronic devices and especially as optical window in modern solar cells.

Influence of Nitrogen Atmosphere Annealing on Structural and Transport Properties of Fe<sub>1.125</sub>Te

Fe1.125Te alloys had been synthesized by solid state reaction methods. The effects of nitrogen annealing on Fe1.125Te lattice structure and physical properties had been studied. It was found that the lattice constants a and c increased after annealed at temperature 400~600 oC. When the temperature is above 850 oC, the size of the unit cell returns to the similar size of original samples. The step-like magnetic-thermal curves were observed after annealed at 900 oC, which is associated with two magnetic transitions. In vacuum, the transition temperatures are 122 K and 128 K, while in the nitrogen, they are 122 K and 138 K. The resistance-temperature curves indicate a semiconductor to metal transition around 69 K for N2 atmosphere.

Nanocrystalline CsxWO3 particles: Effects of N2 annealing on microstructure and near-infrared shielding characteristics

In order to further improve the near-infrared shielding properties of cesium tungsten bronze (CsxWO3) for solar filter applications, CsxWO3 particles were prepared by solvothermal reaction method and the effects of nitrogen annealing on the microstructure and near-infrared shielding properties of CsxWO3 were investigated. The obtained CsxWO3 samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and spectrophotometer. The results indicate that nanosheet-like CsxWO3 particles with hexagonal structure began to transform into nanorods after annealed at temperature higher than 600°C. The near-infrared shielding properties of CsxWO3 particles could be further improved by N2 annealing at 500–700°C. Particularly, the 500°C-annealed CsxWO3 samples in the N2 atmosphere showed best near-infrared shielding properties. It was suggested that the excellent near-infrared shielding ability of the 500°C-annealed CsxWO3 samples is correlated with its minimum O/W atomic ratio and most oxygen vacancies.

Effects of nitrogen annealing on surface structure, silicide formation and magnetic properties of ultrathin films of Co on Si(100)

Effects of nitrogen annealing on structural and magnetic properties of Co/Si (100) up to 700°C has been studied in this paper. Ultrathin Co films having a constant thickness of 50 Å were grown on Si (100) substrates using electron-beam evaporation under very high vacuum conditions at room temperature. Subsequently, the samples were annealed at temperatures ranging from 100–700°C in a nitrogen environment at atmospheric pressure. Sample quality and surface morphology were examined using atomic force microscopy. Silicide formation and the resultant variation in crystallographic arrangement were studied using X-ray diffractometer. The magnetization measurements done using a vibrating sample magnetometer indicate a decrease in coercivity and retentivity values with increase in annealing temperature. Resistivity of the samples measured using a four-point probe set up shows a decrease in resistivity with increase in annealing temperature. Formation of various silicide phases at different annealing temperatures and the resultant variation in the magnetic susceptibility has been thoroughly studied and quantified in this work.

Study on Microstructure and Magnetic Properties of Nitrogen-Annealed Nd-Fe-B Nanocomposite Magnets

The effects of nitrogen annealing on the microstructure and magnetic properties of melt-spun Nd-Fe-Co-Zr-B alloy have been studied. It is shown that the ribbons annealed in purified argon atmosphere are composed of Nd2Fe14B and α-Fe phases, the microstructure of ribbons is homogeneous and fine-grained. The nitrogen-annealed ribbons are composed of Nd2Fe14B, NdBN2and α-Fe phases, the microstructure of ribbons is relatively heterogeneous and coarse-grained. The increase of nitrogen content in the annealing atmosphere can increase the volume fractions of NdBN2and α-Fe phases in the ribbons. The remanence, intrinsic coercivity and the maximum energy product of ribbons are decreased with increasing the nitrogen content in the annealing atmosphere.

Improved aging performance of vapor phase deposited hydrophobic self-assembled monolayers

A hydrophobic self-assembled monolayer (SAM) of fluoro-octyl-trichloro-silane (FOTS) was deposited on silicon using a vapor phase technique. The aging of the hydrophobic layer was examined using water contact angle measurements. It has been found that while such monolayer films suffer from a loss of hydrophobicity with time, pre-immersion nitrogen annealing can significantly improve the aging characteristics of these monolayers. The effect of nitrogen annealing on the improved aging properties of SAM coatings has been investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The hydrolytic stability and the effect of nitrogen annealing were studied by morphological evolution during immersion. A spontaneous formation of silane mounds on the surface of the monolayers was found by AFM. These mounds have been irreversibly transformed from initially uniform hydrophobic surface layers. It is highly probable that the compliance of these mounds can reasonably allow hydrophilic sites to be located around the mounds. Interestingly, the density of these mounds formation is very less on the annealed samples. XPS reveals a higher level of coverage by the N2-annealed film due to agglomeration. A relative abundance of CF3 and CF2 moieties in the annealed film may explain the enhancement of the hydrophobicity as revealed by higher level of water contact angle. This hydrophobicity was found to be significantly stable in water. This novel finding explains the improved hydrophobic stability of FOTS monolayers as primarily a morpho-chemical effect that originates from the densification of the monolayers upon annealing.

Effect of annealing on defect and electrical properties of Mn doped Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 single crystals

Relaxor-based ferroelectric single crystals Mn doped 0.72Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 (Mn–PMN–0.28PT) were grown by the modified Bridgman technique. The effects of nitrogen annealing on structural quality, defect and electrical properties of [111]-oriented Mn–PMN–0.28PT were systematically investigated. X-ray rocking curves (XRC) were used and the results indicated that the quality of single crystals could be significantly improved by appropriate annealing. X-ray photoelectron spectroscopy (XPS) was used to investigate the content and valence states of main elements in Mn–PMN–0.28PT, including oxygen vacancies. The conduction mechanisms at different temperature ranges were discussed. The dielectric loss of annealed samples decreased about 50% compared to the unannealed one, which should be attributed to the motion of domain walls pinned by defects. The pinning effect caused by oxygen vacancies on domain wall motion was enhanced through nitrogen annealing and the pyroelectric performances were optimized.

Study of SILC and interface trap generation due to high field stressing and its operating temperature dependence in 2.2 nm gate dielectrics

Reports study of metal-oxide-semiconductor (MOS) capacitors with 2.2 nm dry and N/sub 2/O grown gate dielectrics. Interface trap generation during constant voltage stressing at different operating temperatures (from 22/spl deg/C to 90/spl deg/C) has been investigated. The effect of nitrogen annealing (20 min) at 400/spl deg/C on high temperature stress-induced interface traps was also studied.

Magnetoresistance and magnetothermopower of nitrogen-annealed RE 1.2Sr 1.8Mn 2O 7+ δ (RE=Nd, Pr)

We report measurements of resistance and thermopower of RE 1.2Sr 1.8Mn 2O 7+ δ (RE=Nd, Pr) ceramics up to a magnetic field of 5 T. Nitrogen annealing has dramatic effects on the transport in reducing the resistivity, shifting peak resistivity to a higher temperature, and shifting thermopower to more negative values. The value of Δ JT increases as a result of nitrogen annealing, indicating an enhanced Jahn–Teller distortion due to the increased Mn 3+ concentration. These results are consistent with the effects of nitrogen annealing on the transport of RE=La.

Effects of nitrogen annealing on electron scatterings in SiSiO 2 interface

The effective mobility of electrons at Si (100) surfaces was measured as a function of electron density N s = 5 × 10 11−1 × 10 13 cm −2 at 4.2K for samples with and without annealing (10 min–2 hr) in nitrogen gas at 1000°C after wet thermal oxidation. A great part of the scattering by Coulomb and short-range potentials was reduced by a short (∼10 min) anneal time, although the subsequent annealing resulted in a slight increase in the number of the scatterers. On the other hand, scattering by a surface roughness potential was reduced with increase in the anneal time. These scattering effects associated with N 2 annealing are discussed.