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1.
Preferred crystal orientation and low electrical resistivity are required for ZrN x films applied in electronic devices. In this paper, effects of N 2:(N 2+Ar) flow ratio ( F(N 2)) and substrate temperature on the properties of the films deposited on glass substrate by reactive dc sputtering are investigated. In a wide range of F(N 2) (4–24%), the films show fcc NaCl structure. While for F(N 2) in the ranges of 5–12, 12–24 and >24%, the films show (1 1 1)/(2 0 0), (1 1 1) only and amorphous structures, respectively. The electrical resistivity increases with F(N 2) from 5 to 24%, and can be controlled to some extent by changing the substrate temperature. 相似文献
2.
It was found that when electrolessly deposited thin Pd and Pd–Cu membranes were exposed to air at temperatures above 350 °C, their H 2 flux increased substantially immediately after the air exposure, then decreased to a new steady-state value. While this was a quasi-reversible change for the H 2 flux, the flux of insoluble species, such as N 2, irreversibly increased with every air exposure but by a much smaller extent. The extent of these changes was found to be dependent on the exposure time and the temperature of the tests. Thus, we decided to investigate the effect of gas exposures on the properties of these materials. Palladium and palladium–copper films, prepared by electroless deposition on ceramic supports, and commercial foils were exposed to air, hydrogen and helium at 500 and 900 °C for times varying from 1 h to 1 week with the objective of determining the effect of the different exposure conditions on the surface morphology, the flux of different penetrants and the crystalline structure of the materials. Atomic force microscopy (AFM) and X-ray diffraction (XRD) were used to study the changes occurring in the films under those conditions. It was observed that the exposure of both the electroless films and the foils to hydrogen and air markedly modified their surface morphology. The hydrogen exposure tended to smooth the surface features whereas the oxygen exposure created new surface features such holes and large peaks. Additionally it was found that the air exposure produced some oxidation of the film to create PdO. These results suggested that a common hypothesis stating that air oxidation just cleans the surface of the membrane might not be sufficient to explain all of those changes. A contributing effect of air exposure may be the increase in surface area due to the formation of palladium oxide. However, the extent of the surface area increase was insufficient to explain the increase in steady-state H2 flux. 相似文献
3.
Carbon nitride thin films were deposited on Si(1 0 0) substrate by microwave plasma-enhanced chemical vapor deposition (PECVD). Hexamethylenetetramine (HMTA) was used as carbon and nitrogen source while N 2 gas was used as both nitrogen source and carrier gas. The sp 3-bonded C---N structure in HMTA was considered significantly in the precursor selection. X-ray diffraction analysis indicated that the film was a mixture of crystalline - and β-C 3N 4 as well as graphitic-C 3N 4 and β-Si 3N 4 which were not easily distinguished. Raman spectroscopy also suggested the existence of - and β-C 3N 4 in the films. X-ray photoelectron spectroscopy study indicated the presence of sp 2- and sp 3-bonded C---N structures in the films while sp 3C---N bonding structure predominated to the sp 2 C---N bonding structure in the bulk composition of the films. N was also found to be bound to Si atoms in the films. The product was, therefore, described as CN x:Si, where x depends on the film depth, with some evidences of crystalline C 3N 4 formation. 相似文献
4.
A new method in preparing carbon-based molecular sieve (CMS) membranes for gas separation has been proposed. Carbon-based films are deposited on porous Al 2O 3 disks using hexamethyldisiloxane (HMDSO) by remote inductively coupled plasma (ICP) chemical vapor deposition (CVD). After treating the film with ion bombardment and subsequent pyrolysis at a high temperature, carbon-based molecule sieve membranes can be obtained, exhibiting a very high H 2/N 2 selectivity around 100 and an extremely high permeance of H 2 around 1.5 × 10 −6 mol m −2 s −1 Pa −1 at 298 K. The O 2/N 2 selectivity could reach 5.4 with the O 2 permeance of 2 × 10 −7 mol m −2 s −1 Pa −1 at 423 K. During surface treatments, HMDSO ions were found to be more effective than CH4, Ar, O2 and N2 ions to improve the selectivity and permeance. Short and optimized surface treatment periods were required for high efficiency. Without pyrolysis, surface treatments alone greatly reduced the H2 and N2 permeances and had no effect on the selectivity. Besides, without any surface treatment, pyrolysis alone greatly increased the H2 and N2 permeances, but had no improvement on the selectivity, owing to the creation of large pores by desorption of carbon. A combination of surface treatment and pyrolysis is necessary for simultaneously enhancing the permeance and the selectivity of CMS membranes, very different from the conventional pore-plugging mechanism in typical CVD. 相似文献
5.
采用射频磁控溅射方法, 在低功率和低温条件下利用纯氮气作为反应溅射气体制 备出不同In含量的三元氮化物Cu xIn yN薄膜. 研究发现In掺杂浓度对薄膜微结构、形貌、表面化学态以及光学特性有灵敏的调节作用. 光电子峰、俄歇峰、俄歇参数的化学位移变化从不同角度揭示了不同含量In掺杂引 起的原子结合情况的变化. XPS结果显示In含量小于8.2 at.%的样品形成了Cu-In-N键. 对In含量为4.6 at.%的样品进行XRD和TEM结构测试, 实验结果肯定了In原子填充到Cu 3N的反ReO 3结构的体心位置. 并且当In含量增至10.7 at.%时, 薄膜生长的择优取向从之前占主导地位的(001)方向转变为(111)方向. 此外, 随着In含量的增加, 薄膜的R-T曲线从指数形式变为线性. 当In含量为47.9 at.%时, 薄膜趋于大温区恒电阻率材料, 电阻温度系数TCR仅为-6/10000. 光谱测量结果显示In摻杂使得氮化亚铜掺杂薄膜的光学帯隙从间接帯隙变为直接帯隙. 由于Burstein-Moss效应, 帯隙发生蓝移, 从1.02 eV 到2.51 eV, 实现了帯隙连续可调.
关键词:
三元氮化物
薄膜
光学特性
氮化亚铜 相似文献
6.
High quality gallium nitride thin films have been successfully grown on the Ga-diffused Si(1 1 1) substrates through ammoniating Ga 2O 3 thin films deposited by r.f. magnetron sputtering. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), atomic force microscope (AFM) and photoluminescence (PL) were used to characterize the synthesized samples. The analyses reveal that the formed films are high quality polycrystalline hexagonal gallium nitride. The as-formed GaN films show a flat surface topography with RMS roughness varied from 29 to 48 Å. The strong near-band-edge-emission peak around 368 nm was observed at room temperature. This is a novel method to fabricate GaN thin films based on the direct reaction between Ga 2O 3 and NH 3 on the Ga-diffused Si(1 1 1) substrates. 相似文献
7.
Nd 1.85Ce 0.15CuO 4−δ superconducting thin films were prepared on (1 0 0) SrTiO 3 substrates by pulsed electron deposition technique without reducing atmosphere. Oxygen content is finely controlled by high temperature vacuum annealing, and optimal superconductivity has been obtained. The deposition conditions of the film are discussed in details. Higher deposition temperature and lower gas pressure result in the loss of copper and the appearance of the foreign phase Ce 0.5Nd 0.5O 1.75. High quality Nd 1.85Ce 0.15CuO 4−δ epitaxial films are deposited at 840–870 °C in the mixed gas with a ratio of O 2:Ar = 1:3. 相似文献
8.
以市场上销售的国内改色紫红色圆刻面型钻石为研究对象,通过对其光谱学特征进行分析,确定了此类紫红色改色处理钻石的鉴定。样品颜色呈现不同饱和度的紫红色,净水称重法测试比重为3.52,放大观察,样品DR-2与DR-3的部分刻面光泽较弱,显示了未被重新抛光的严重烧蚀区域,石墨化沿内应力断裂明显,其表面可能经过高温高压处理。365nm长波紫外下,均呈现蓝色、橙红色、黄色和绿色混合的白垩状荧光外观,无磷光现象,而天然紫红色钻石为蓝色荧光或无荧光。宽频诱导发光图像仪GV5000深紫外下均呈现橙红色和蓝色混合荧光,无磷光现象。红外光谱中红外区均显示集合体氮相关的A中心和B中心,归类为IaAB型,且具有H1a辐照退火相关的特征峰,红外光谱近红外区均显示H1b,H1c辐照退火相关的特征峰与H 2中心的特征峰。紫外可见近红外分光光度计均显示明显的NV-中心,H 2中心和806 nm吸收峰,400~460和570 nm宽带处反射率的变化分别与N 3中心和NV0中心相关,明显的NV-中心在天然紫红色钻石中极少发现,H 2中心指示可能经过高温高压处理,可见光范围内对红光和蓝光的吸收较弱,所以呈现为紫红色外观。三维荧光光谱和光致发光光谱均显示出N 3,H 3,H 4,NV0, NV-相关的发光中心,N 3贡献蓝色荧光,H 3和H 4贡献黄绿色荧光,NV0与NV-贡献橙红色荧光。综合分析,三颗样品均为天然成因的钻石,后期经过高温高压,辐照,退火等多重处理,其紫红色主要由N 3中心,NV0中心与NV-中心共同贡献。 相似文献
9.
FeN thin films were deposited on glass substrates by dc magnetron sputtering at different Ar/N 2 discharges. The composition, structure and the surface morphology of the films were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and atomic force microscopy (AFM). Films deposited at different nitrogen pressures exhibited different structures with different nitrogen contents, and the surface roughness depended on the mechanism of the film growth. Saturation magnetization and coercivity of all films were determined using superconducting quantum interference device, which showed that if N 2/(Ar+N 2) flow ratio was equal to or larger than 30% the nonmagnetic single-phase γ″-FeN appeared. If N 2/(Ar+N 2) flow ratio was less than 10%, the films consisted of the mixed phases of FeN 0.056 and γ′-Fe 16N 2, whose saturation magnetizations were larger than that of -Fe. If N 2/(Ar+N 2) flow ratio was 10%, the phases of γ′-Fe 4N and -Fe 3N appeared, whose saturation magnetizations were lower than that of -Fe. 相似文献
10.
Thin films of perovskite manganite, with nominal composition La 0.5Ca 0.5MnO 3, have been prepared by pulsed laser deposition on (1 0 0) SrTiO 3, (1 0 0) LaAlO 3, (1 0 0) Si and YSZ/CeO 2-buffered (1 0 0) Si substrates. Structural and electrical characterisation was performed on the films. The magneto-transport properties of all the thin films depart from the bulk behaviour. The LCMO film grown on buffered Si shows an insulator–metallic transition around 130–150 K while the one deposited directly on Si displayed a similar behaviour under a melting field of 1 T. However, that transition is absent in the films grown on LAO and STO. We suggest that appropriate stress values induced by the substrate favour the formation of metallic percolative paths. 相似文献
11.
The thermal and native oxidation of CuGaSe 2 thin films was studied by in situ X-ray photoelectron spectroscopy (XPS). The special design of the XPS chamber allowed to measure XP-spectra under oxidizing gas atmospheres at pressures of up to 5 mbar (in situ) or in ultra high vacuum (UHV). During thermal oxidation, the formation of predominantly Ga 2O 3 and some amount of SeO 2 were observed, but no copper oxides could be detected in the near surface region of the thin films. The same oxides were found after native oxidation in air under ambient conditions. Only after long term native oxidation for longer than 4 months Cu(OH) 2 was detected. An additional sodium oxide compound formed at the thin film surface, Na xO and Na 2CO 3 after thermal and native oxidation, respectively. The amount of these sodium oxide compounds depends on the Na content on the as prepared surface. The formation of SeO 2 under humid conditions at 100 °C was found to depend on the surface composition of the thin film. 相似文献
12.
Ti substituted BiFe 1−xTi xO 3+δ films have been prepared on indium–tin oxide (ITO)/glass substrates by the sol–gel process. The films with x=0.00–0.20 were prepared at an annealing temperature of 600 °C. X-ray diffraction patterns indicate that all films adopt R3m structure and the films with x=0 and 0.10 show pure perovskite phase. Cross-section scanning shows the thickness of the films is about 300 nm. Through 0.05 Ti substitution, the 2 Pr increases to 8.30 μC/cm 2 from 2.12 μC/cm 2 of the un-substituted BiFeO 3 film and show enhanced ferroelectricity at room temperature. The 2 Pr values are 2.63 and 0.44 μC/cm 2 for the films with x=0.01 and 0.2, respectively. Moreover, the films with x=0.05 and 0.10 show enhanced dielectric property since the permittivity increases near 150 at the same measuring frequency. Through the substitution of Ti, the leakage conduction is reduced for the films with x=0.05–0.20. 相似文献
13.
A multipolar plasma passivation scheme controlled by in-situ ellipsometry has been developed to produce a high electrical quality InGaAs/Si 3N 4 interface. We have demonstrated the possibility to remove all native oxides at the InGaAs surface by heating the sample at 240°C, then using the action of a multipolar H 2 plasma at 185°C, without optical degradation of the surface. The passivation by a native nitride layer is then performed using a N 2 plasma, and Si 3N 4 is deposited. The treatment induces a reduction of the density of interface states Nss( E), and also a change of the nature of these interface states as shown by a reduction in the capture cross section σ n( E). 相似文献
14.
Pure and rare earth doped gadolinium oxide (Gd 2O 3) waveguide films were prepared by a simple sol–gel process and dip-coating method. Gd 2O 3 was successfully synthesized by hydrolysis of gadolinium acetate. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study the thermal chemistry properties of dried gel. Structure of Gd 2O 3 films annealed at different temperature ranging from 400 to 750 °C were investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that Gd 2O 3 starts crystallizing at about 400 °C and the crystallite size increases with annealing temperature. Oriented growth of (4 0 0) face of Gd 2O 3 has been observed when the films were deposited on (1 0 0) Si substrate and annealed at 750 °C. The laser beam (λ=632.8 nm) was coupled into the film by a prism coupler and propagation loss of the film measured by scattering-detection method is about 2 dB/cm. Luminescence properties of europium ions doped films were measured and are discussed. 相似文献
15.
利用射频磁控溅射方法,使用Mg 0. 04Zn 0.96O 陶瓷靶材,选用不同流量比的氮气和氩气混和气体作为溅射气体,在石英基片上生长N掺杂Mg xZn 1-xO合金薄膜。研究了氮流量比对薄膜组分、结构、形貌、电学性质和拉曼光谱的影响。结果显示:随着溅射气氛中氮流量比的增加,薄膜中Mg含量增加,薄膜表面颗粒尺寸减小,结晶质量变差,电阻率逐渐增大,导电类型发生转变。在氮流量比为20%时,获得了最好的p型导电薄膜。另外,随着氮流量比的增加,拉曼光谱中与N O相关的位于272 cm -1、642 cm -1左右的振动峰逐渐增强,表明N O的浓度随着氮流量比的加大而有所增加。 相似文献
16.
Well-crystallized Ba 0.5Sr 0.5TiO 3 thin films with good surface morphology were prepared on MgO(1 0 0) substrates by pulsed laser deposition technique at a deposition temperature of 800 °C under the oxygen pressure of 2 × 10 −3 Pa. X-ray diffraction and atomic force microscopy were used to characterize the films. The full width at half maximum of the (0 0 2) Ba 0.5Sr 0.5TiO 3 rocking curve and the root-mean-square surface roughness within the 5 μm × 5 μm area were 0.542° and 0.555 nm, respectively. The nonlinear optical properties of the films were determined by a single beam Z-scan method at a wavelength of 532 nm with laser duration of 55 ps. The results show that Ba 0.5Sr 0.5TiO 3 thin films exhibit a fast third-order nonlinear optical response with the nonlinear refractive index and nonlinear absorption coefficient being n2 = 5.04 × 10 −6 cm 2/kW and β = 3.59 × 10 −6 (m/W), respectively. 相似文献
17.
Cadmium selenide (CdSe) thin films have been electrodeposited on the titanium or ITO substrate in an electrolyte containing CdSO 4 and H 2SeO 3 at pH = 2.50 and temperature 298 K. Influence of different deposition potentials on the surface morphology and crystal structure of CdSe films has been discussed. Compared with other deposition potentials (−0.65, −0.71 and −0.72 V versus SCE), the nearly stoichiometric CdSe nanocrystalline films with smaller grain sizes of 80 nm were obtained from 0.25 M CdSO 4 + 0.25 mM H 2SeO 3 + 0.25 M Na 2SO 4 solution at deposition potential of −0.70 V versus SCE. X-ray diffraction, atomic force microscope and scanning electron microscope were used to measure structure and morphology of CdSe films. The results indicated that the electrodeposited films were the smooth, compact and uniform at deposition potentials of −0.70 V versus SCE. 相似文献
18.
Silicon nanocrystals have been synthesized in SiO 2 matrix using Si ion implantation. Si ions were implanted into 300-nm-thick SiO 2 films grown on crystalline Si at energies of 30–55 keV, and with doses of 5×10 15, 3×10 16, and 1×10 17 cm −2. Implanted samples were subsequently annealed in an N 2 ambient at 500–1100°C during various periods. Photoluminescence spectra for the sample implanted with 1×10 17 cm −2 at 55 keV show that red luminescence (750 nm) related to Si-nanocrystals clearly increases with annealing temperature and time in intensity, and that weak orange luminescence (600 nm) is observed after annealing at low temperatures of 500°C and 800°C. The luminescence around 600 nm becomes very intense when a thin SiO 2 sample is implanted at a substrate temperature of 400°C with an energy of 30 keV and a low dose of 5×10 15 cm −2. It vanishes after annealing at 800°C for 30 min. We conclude that this luminescence observed around 600 nm is caused by some radiative defects formed in Si-implanted SiO 2. 相似文献
19.
A study of the physical and chemical changes during processing in MOD-derived YBCO films was performed. Fully processed films were 70–85% of theoretical density. The sintering rate increased substantially in the compositional range F/Ba = 1.8–1.5. The activation energy for sintering decreased above a P(H 2O) dependent threshold temperature. XRD indicated this temperature/composition threshold also corresponded to YBCO nucleation, suggesting ex situ YBCO forms in contact with a melt. The ramp rate and P(H 2O) were used to control F/Ba trajectories, which were correlated to performance. The nucleation of YBCO was strongly dependent on processing conditions. Nucleation temperature was varied by at least 60 °C in the study. The optimal YBCO nucleation temperature in the 300–800 nm films was around 725 °C. a-axis grains dominated the microstructures of films where YBCO nucleated at <700 °C. Large second phases, but no a-axis grains, were found when the nucleation temperature was >750 °C. 相似文献
20.
The textural properties, morphological features, surface basicity and oxygen reduction behaviours of titania and Pt supported titania catalysts synthesized via a sol–gel method were studied by means of N 2 physisorption, SEM, TEM, CO 2-TPD and H 2-TPR techniques. Mesostructured TiO 2 shows a very narrow pore size distribution that uniformly centred at about 4 nm. High resolution TEM images confirmed that most of Pt particles on Pt/TiO 2-SG had a size smaller than 2 nm. Both the titania support and Pt loaded catalysts chiefly contained weak basic sites with small amount of strong basic sites. Loading Pt did not significantly alter the surface reduction characters of titania, indicating a weak interaction between Pt metals and titania support. Catalytic evaluation revealed that the selectivity of NO reduction over titania was insensitive to variation of textural property. On the bare titania, low NO conversion but high selectivity to N 2O was obtained. However, the Pt/TiO 2-SG catalysts exhibited high NO conversion and high selectivity to N 2, which is assumed to relate to NO dissociation catalysed by the metallic Pt clusters. In addition, when the reaction temperature was above 200 °C, 3–11% NO 2 was yielded over the Pt/TiO 2-SG catalysts, which was discussed on a basis of reaction competition, metal-support interaction and NO dissociation. 相似文献
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