Structure and magnetic properties of columnar Fe-N thin films deposited by direct current magnetron sputtering

Columnar Fe-N thin films with thickness ranging from 30 to 150 nm were deposited by direct current magnetron sputtering using an Ar/N2 gas mixture (V(N2)/V(N2+Ar)=5%) on corning glass substrates. The structure, surface morphology and magnetic properties were investigated using X-ray diffractometry(XRD), scanning electron microscopy, atomic force microscopy, transmission electron microscopy(TEM) and superconducting quantum interference magnetometry. XRD investigation shows that Fe-N films exhibit amorphous-like structures; however, TEM measurements indicate the synthesis of mixture phases of α-Fe+ζ-Fe2N+ε-Fe3N in these films. The magnetic anisotropy and coercivity of Fe-N thin films exhibit strong dependence on the film growth behavior and surface morphology. With increasing the height of Fe-N films with column structures, the coercivity increases from 7.96 kA/m to 22.28 kA/m in the direction parallel to the film surface. In perpendicular direction the coercivity only increases slightly from 39.79 kA/m to 43.77 kA/m. However, the values of anisotropy field increase from 0.79×106 to 1.44×106 A/m, which is mainly attributed to the shape anisotropy of elongated columns due to the fact that the difference of magneto-crystalline anisotropy among these Fe-N films is small. The saturation magnetizations of Fe-N films vary with increasing film thickness from 23.5 to 85.1 A-m2/kg.     

AN HREM STUDY OF A LATERAL MICROCRACK BENEATH INDENTATION OF [001] SILICON

1.IntroductionTherearetwoldndsofopinionsinunderstandingthemicromechedsmoffractureofbrittlematerials,i.e.,theductiletearingtype,arisingfromthedislocationemissionfromthecraCktip,andthebrittletype,resultingfromthesuccessivebondrupture.Itiswenacceptedthatthestructureofdefects(suchasdislocations)incryStalsnearthecraCktipdetermineswhatkindoffracturethecraCkis[1'21.ForobserVationonthecraCktip,transmissionelectronmicroscopy(TEM),especiajlyhighresolutionelectronmicroscopy(HREM),playsanimportantrol…     

THE STABILITY INVESTIGATION OF FERROELECTRIC SrBi_2Ta_2O_9 THIN FILMS ANNEALED IN FORMING GAS

The hysteresis loop changes of ferroelecric SrBi2Ti2O9 (SBT) thin films (330nm) vs the temperature of forming gas (5% hydrogen 95% nitrogen) annealing were measured when the annealing time was 1min and 10min. The selected annealing temperature was at 100℃, 200℃, 250℃, 300℃, 350℃, 400℃ and 450℃, respectively. Our results showed that the ferroelectric properties were easily destroyed and the leakage current changed abruptly when the SBT thin films were in their ferroelectric phase (<270℃). The space charges at the grain boundary may take an important role in absorption polarity molecular hydrogen when the SBT thin films were in the ferroelectric phase. The oxygen recovery experiments were also performed and investigated in this work.     

等离子合金化/热氧化复合技术制备光催化N掺杂TiO2薄膜

目的 提高316 L不锈钢表面的光催化和亲水性能.方法 通过等离子表面合金化技术在316 L不锈钢表面制备结合良好的TiN薄膜,然后对TiN薄膜进行热氧化,得到N掺杂TiO2薄膜.利用X射线衍射仪、X射线光电子能谱仪、扫描电子显微镜及紫外-可见分光光度仪对制备的N掺杂TiO2薄膜进行表征,并通过光催化实验和亲水性实验考察其光催化性能和亲水性.结果 经过空气中450℃氧化处理2 h的薄膜中存在锐钛矿晶型的TiO2,样品中的N元素取代了部分O.未掺杂TiO2和N掺杂TiO2的带隙宽度分别为3.25、3.08 eV.经热氧化处理后,薄膜表面致密,无裂纹和微孔,均匀分布着尺寸相近的微小凸起物.经可见光照射150 min后,N掺杂TiO2薄膜对亚甲基蓝溶液的最终降解率为20%.此外,N掺杂TiO2薄膜具有较高的亲水性,可见光照射下,30min内接触角降为8.5°.结论 N掺杂TiO2薄膜能有效提高316 L不锈钢表面的光催化和亲水性能.     

High resolution electron microscopy characterization of nitrides of iron and iron alloys

A study of nitride-phase formation in alloys nitrided by glow discharge plasma nitriding was performed by high-resolution electron microscopy. The iron and steel samples were nitrided above and below the eutectoid transformation point (590 ‡C). After nitriding, the samples were annealed for several treatment times at 400 ‡C. The microstructure and identification of the iron nitrided phases formed by nitriding and annealing were investigated by x-ray diffraction (XRD), optical microscopy (OM) and mainly high resolution electron microscopy (HREM) in a JEOL-4000EX high resolution microscope at 400 kV. The results of the characterization show a surface ε compact nitride layer, which is transformed into ε + γ during cooling. The tempering process affects the surface hardness of the samples. After an initial increase relative to the untreated sample, the microhardness diminishes after long treatment times. This behavior is correlated with the αt’’ phase appearance, growth, and transformation.     

碳化硼薄膜的电子束蒸发制备及表面分析

采用电子束蒸发技术制备碳化硼薄膜,利用X射线衍射(XRD)分析了薄膜的结构,测量了薄膜的X射线光电子能谱(XPS),并利用原子力显微镜(AFM)对薄膜进行表面分析.XRD结果表明:薄膜的结晶性随着衬底温度的升高逐渐转好,在较低的衬底温度下制备出多晶碳化硼薄膜.XPS分析得到了碳化硼薄膜表面的化学成分和结构特性,其主要成分为B_4C.AFM结果表明,薄膜表面光滑平整、均匀致密,随着衬底温度的升高薄膜均方根(RMS)粗糙度逐渐增大.     

超声波对Ta/SiO2/Si基板置换活化法化学镀铜的影响

采用置换活化法,以PdCl2/BOE/HNO3溶液对Ta/SiO2/Si基板进行活化,然后在基板上成功实现化学镀Cu薄膜。应用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)等方法,研究了活化时间及超声波对化学镀Cu薄膜表面形貌和结构的影响。结果表明,在化学镀Cu过程中没有引入超声波时,随着活化时间由30 s增加到150 s,Cu膜覆盖率逐渐降低;在引入超声波以后,随着活化时间的增加,Cu膜覆盖率始终很高。XRD分析表明,引入超声波以后,Cu(111)和(200)峰的衍射强度明显增加,当活化时间为60 s时,Cu(111)和(200)峰的强度比I(111)/I(200)达到4.53。对具有沟槽的Ta/SiO2/Si基板进行化学镀Cu的结果表明,引入超声波,可以明显改善对沟槽的填充效果     

磁控溅射法ZnO-TiO2复合薄膜的制备及性能

采用双靶共溅射的方法在FJL600EI型超高真空多功能磁控溅射仪上制备不同复合量的ZnO-TiO2复合薄膜,对不同工艺参数制备的ZnO-TiO2复合薄膜进行形貌结构分析、光催化性测定和亲水性检测。结果表明,当Ti靶材的溅射功率为150 W时,得到了颗粒大小均匀的ZnO-TiO2复合薄膜,且复合薄膜对甲基橙的降解率最高,亲水性最优。ZnO-TiO2薄膜的光催化性明显高于单一ZnO薄膜。     

Effect of sputtering pressure and rapid thermal annealing on optical properties of Ta2O5 thin films

Ta2O5 thin films were deposited by DC reactive magnetron sputtering followed by rapid thermal annealing(RTA). Influence of sputtering pressure and annealing temperature on surface characteristics, microstructure and optical property of Ta2O5 thin films were investigated. As-deposited Ta2O5 thin films are amorphous. It takes hexagonal structure (δ-Ta2O5) after being annealed at 800 ℃. A transition from δ-Ta2O5 to orthorhombic structure (L-Ta2O5) occurs at 900-1 000 ℃. Surface roughness is decreased after annealing at low temperature. Refractive index and extinction coefficient are decreased when annealing temperature is increased.     

基体温度对磁控溅射TiN薄膜电化学性能的影响

采用直流反应磁控溅射方法在AISI 304不锈钢和Si(100)表面沉积了TiN薄膜,利用场发射扫描电镜、X射线衍射仪和电化学技术研究了基体温度对TiN薄膜结构与电化学性能的影响。结果表明:TiN薄膜为柱状结构,表面平整、致密,但基体温度高于300℃时膜表面存在微裂纹。薄膜为面心立方结构δ-TiN并存在择优取向,室温和150℃时的薄膜择优取向为(111)晶面,300℃和450℃时为(200)晶面;基体为室温时薄膜厚度为0.63μm,温度提高到150℃后膜厚增加到1μm左右,但继续升温对膜厚影响并不明显。薄膜在NaCl溶液中的腐蚀为点蚀,基体温度为150℃时的TiN薄膜具有最高的开路电位和点蚀电位以及最低的腐蚀速率,因此具有最佳的耐蚀性。     

磁过滤阴极弧法制备CrCN薄膜结构与组分研究

目的通过磁过滤阴极弧沉积技术制备质量优异的CrCN涂层。研究乙炔/氮气混合气体流量以及基底偏压对薄膜结构和成分的影响。方法采用磁过滤真空阴极弧沉积技术,在20~100 m L/min变化的乙炔/氮气混合气体流量参数下沉积CrCN复合薄膜。通过X射线衍射、场发射电子显微镜、扫描探针显微镜、X射线光电子能谱仪、透射电镜,对薄膜的物相结构和形貌进行分析。结果随着气体流量的增加,CrCN复合薄膜的晶粒逐渐减小最终向非晶化转变。TEM结果表明,在CrCN复合薄膜中有大量几纳米到十几纳米的纳米晶浸没在非晶成分中。SPM表明,随着基底偏压由–200 V增大到–150 V,CrCN薄膜的表面粗糙度Sa由0.345 nm上升至4.38 nm。XPS、TEM和XRD数据表明,薄膜中Cr元素主要以单质Cr、Cr N以及Cr3C2的形式存在。结论采用磁过滤真空阴极弧沉积技术制备的CrCN复合薄膜具有纳米晶-非晶镶嵌结构。该方法沉积的CrCN薄膜的表面粗糙度与基底负偏压有关。混合气体的流量变化对薄膜组分的变化几乎无影响。     

Preparation and characterization of nanostructured Bi_2Se_3 and Sn_(0.5)-Bi_2Se_3

Nanostructured Bi2Se3 and Sn0.5·Bi2Se3 were successfully synthesized by hydrothermal coreduction from SnCl2-H2O and the oxides of Bi and Se. The products were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and field emission scanning electron microscope (FESEM). Bi2Se3 powders obtained at 180°C and 150°C consist of hexagonal flakes of 50-150 nm in side length and nanorods of 30-100 nm in diameter and more than 1 μm in length. The product obtained at 120°C is composed of thin...     

Ta/[NdFeB/Nd]_n/Ta(n=1,5,8,10)多层膜磁性能研究

采用磁控溅射法制备了Ta/[Nd Fe B/Nd]n/Ta(n=1,5,8,10)多层膜。采用X射线衍射仪、振动样品磁强计及原子力显微镜对薄膜样品的晶体结构、磁学性能及表面形貌进行了测试分析;并对薄膜的温度稳定性进行了测试。结果表明,在Nd Fe B与Nd的总厚度保持不变的情况下,随Nd Fe B/Nd层数的增加薄膜的矫顽力先增大后减小,其中n=8时样品磁性能最好。最佳磁性能为H ci=1995 k A/m,(BH)max=111.3 k J/m3。     

FERROELECTRIC CHARACTERISTICS OF SrBi2Ta2O9 THIN FILMS ANNEALED IN FORMING GAS

1. IlltroductionRecently, SrBi2Ta2O9 (SBT) thin films had been attracting considerable attention forapplication to nonvolatile ferroelectric random access memory (FeRAM). It had been re-ported that SBT thin films had superior properties of free--fatigue and Iow leakage currentllJ.However, it was a serious problem that fOrming gas (5%H2+95%N2) annealing could causethe severe degradation of SBT thin films in ferroelectric polarization. It had been suggestedthat the origin of H2 damage …     

Microstructure and properties of indium tin oxide thin films deposited by RF-magnetron sputtering

Tin-doped indium oxide （ITO） thin films were prepared using conventional radio frequency （RF） planar magnetron sputtering equipped with IR irradiation using a ceramic target of In2O3/SnO2 with a mass ratio of 1：1 at various IR irradiation temperatures T1 （from room temperature to 400℃）. The refractive index, deposited ratio, and resistivity are functions of the sputtering Ar gas pressure. The microstructure of ITO thin films is related to IR T1, the crystalline seeds appear at T1= 300℃, and the films are amorphous at the temperature ranging from 27℃ to 400℃. AFM investigation shows that the roughness value of peak-valley of ITO thin film （Rp-v） and the surface microstructure of rio thin films have a close relation with T1. The IR irradiation results in a widening value of band-gap energy due to Burstein-Moss effect and the maximum visible transmittance shifts toward a shorter wavelength along with a decrease in the film＇s refractive index. The plasma wavelength and the refractive index of ITO thin films are relative to the T1. XPS investigation shows that the photoelectrolytic properties can be deteriorated by the sub-oxides. The deterioration can be decreased by increasing the oxygen flow rote （fo2）, and the mole ratio of Sn/In in the samples reduces with an increase info2.     

两相界面几何错配的高分辨电子显微象分析

从界面两相的几何参数出发,计算界面两侧点阵平面的错配,并用实验观测的界面位错排布加以证实,这是相间界面分析的常用方法。本文进一步分析了那些从几何失配来预言界面会出现失配位错,但高分辨电子显微象却显示良好匹配的情况。说明在一定条件下,两相的结构相似性会容纳较大的几何失配。     

表面修饰TiO2光催化薄膜的表征

利用射频磁控溅射技术，以Ar和O2气混合气体为溅射气体在载玻片上制备了锐钛相TiO2薄膜。为了提高Ti02薄膜的光催化活性，在TiO2薄膜表面进行了钽修饰。利用X射线衍射(XRD)，原子力显微镜(AFM)和UV-VIS-NIR分光光度计等技术对薄膜进行了表征。结果表明：对TiO2薄膜的表面进行适量的Ta元素修饰可以提高其光催化活性。     

氮气流量对磁控溅射法沉积NGZO薄膜性能的影响

目的通过磁控溅射镀膜工艺,在玻璃上制备高质量的氮镓共掺杂氧化锌(NGZO)薄膜。方法采用射频磁控溅射法,同时通入氩气和氮气,在流量比分别为25/10、25/20、25/25、25/30((m L/min)/(m L/min))条件下制备NGZO薄膜。通过XRD和SEM对薄膜的物相结构和表面形貌进行分析,通过紫外/可见分光光度计和霍尔效应测试仪对薄膜透过率和载流子浓度、迁移率及薄膜电阻率进行研究。结果与未掺入N的Ga掺杂氧化锌(GZO)薄膜相比,在可见光区,尤其是600~800 nm范围内,NGZO薄膜平均透过率在80%以上,符合透明导电薄膜透过率的要求。GZO薄膜载流子浓度较高,电阻率较低,而掺入N后薄膜的载流子浓度和迁移率有所下降,电阻率有所增加。结论在N-Ga共掺杂薄膜中,N的掺杂主要占据O空位,并吸引空位周围的电子,这减小了薄膜晶格畸变,并产生电子空穴,最终使得薄膜中电子载流子浓度降低,空穴载流子浓度增加,电阻率有所增加。随着氮气流量的变化,发现在25 m L/min时,薄膜具有最佳的综合性能。这种薄膜可用于紫外光探测器等需较大电阻率的应用中,并有望实现n-p型转化。     

Phase structure and fine microstructure of in-situ vanadium carbides in cast high-vanadium high-speed steel

The phase structure and fine-microstructure of in-situ vanadium carbide formed during solidification in cast high-speed steel were studied and observed through high resolution electron microscope (HREM). In addition, the different micro-area compositions in vanadium carbide were analyzed via energy-dispersive spectroscopy (EDS). The results show that vanadium carbides are characterized by large amounts of MC-type nano-particles carbides, an enriched Mo element, distributed in a matrix composed of VC (FCC lattice) and V₆C₅ (HCP lattice). MC-type nano-particles are coherent or partially coherent with a matrix of vanadium carbide.     

电子晶体学图像处理及其在材料科学中的应用

本文指出，借助高分辨电子显微镜观察到的显微像并不总直观地反映晶 体结构，对于在特定离焦条件下拍摄到的结构像，其分辨率还要受显微镜分辨本领的限制，只有超高压高分辨电子显微镜才能直接给出原子分辨率的结构像。文章介绍了衍射晶体学与高分辨电子显微学相结合起来的优越性，和据此发展的电子晶体学图像处理技术，用此技术可以实现“从头”测定晶体结构，并能把中等电压电子显微镜得到的结构像分辨率约提高1倍，达到原子分辨率。文中举例介绍了此技术在测定晶体结构和缺陷中的应用。