Effects of substrate material and annealing temperature on morphology of zinc oxide films

Abstract

A two stage chemical deposition (TSCD) technique is used to produce ZnO films on quartz glass (QG), soda lime glass (SLG) and high purity alumina (HPA) from an aqueous solution of zinc complex. The effects of the substrate material on the chemical composition and morphology of the deposited layer are investigated. The effects of different annealing temperatures (180, 300, 500 and 800°C) on the morphology and orientation of the ZnO crystallites are also determined. X-ray diffraction diffractograms show that above 300°C, the intensity of (002) peak considerably decreases with increasing temperature. Results indicate that changing the substrate from QG to SLG does not significantly influence the chemical composition of the deposited layer. These variations can be attributed to different factors including (a) physorption of cold complex solution, (b) growth behaviour of the nuclei forming on the substrate and (c) the surface energy of the substrate. Owing to the existence of the morphological differences bound to the molecular nature of the substrate, properties of the coatings are found not to be the same. HPA substrate causes clustering of the ZnO crystallites, while QG and SLG substrates do not distinguishably show this effect. Observations show that clustering is intensified by annealing at temperatures > 180°C.     

MBE growth and characterization of buried silicon oxide films on Si(100)

Silicon molecular beam epitaxy (Si-MBE) has been used to produce silicon oxide (SiO_x) films by evaporating Si on a heated Si(100) substrate in an ultra high vacuum system with an O₂ pressure of 10⁻⁶ to 10⁻⁴ mbar. Then the SiO_x films were overgrown with pure Si. The influence of the substrate temperature, the O₂ pressure and the Si deposition rate on the oxygen content in the SiO_x films and on the crystalline quality of the Si top-layer was investigated by Rutherford backscattering spectrometry and ion channeling. Epitaxial growth of the Si top-layer was observed up to a maximum concentration of ≈20 at.% oxygen content in the SiO_x film. Cross-sectional transmission electron microscopy shows that the structure of the SiO_x film changes duringa subsequent annealing procedure. Electron energy loss spectrometry proves that amorphous SiO₂ is formed and the development of holes indicates that the density of the as-grown SiO_x film is much lower than that of SiO₂. The specific for the as-grown SiO_x films was determined by I–V measurements.     

Ferromagnetism and ferromagnetic resonance in Mn and As co-implanted Si and GaAs

Ferromagnetism persisting above 375 K and anisotropic ferromagnetic resonance (FMR) spectra have been detected for the first time in Si co-implanted with Mn and As and annealed under appropriate conditions. For comparison, semi-insulating GaAs samples have been implanted with the same ions and subsequently annealed. They also exhibit ferromagnetism with a Curie temperature well in excess of 375 K. High-resolution transmission electron microscopy (HR TEM) performed on the samples with the best magnetic characteristics has shown the presence of nanoclusters due to the segregation of the implanted species in both Si and GaAs. The angular dependence of the FMR spectra reveals the existence of magnetic entities with the hard magnetization axes aligned along the four equivalent 〈1 1 1〉 crystal axes. The spectra are very similar in Si and GaAs, indicating that hexagonal MnAs clusters might be formed in Si.     

Effects of temperature and magnetization on the maximum solubility of 3He in 4He

The laws x^m=x^m(T=0)(1+ _T T²) and x^m=x^m(B=0)(1+ _M B²), giving the effects of temperature and magnetization on the maximum solubility of ³He in ⁴He, are derived using the theory of normal Fermi systems. The parameters _T and _M are expressed in terms of measurable quantities, such as the specific heat and the magnetic susceptibility of the pure and dilute phases. Our relations are consistent with the experimental measurements of _T at SVP and predict a significant dependence of _T on pressure. Estimates of the parameter _M are given. The effects of temperature and magnetization on the osmotic pressure are also discussed.INFN sezione di Padova, gruppo collegato di Trento.     

高温退火法制备氧化石墨烯

以天然鳞片石墨为原料,采用高温退火法一步制备氧化石墨,然后经水解、超声分散制备氧化石墨烯。采用透射电子显微镜(TEM)、X射线衍射(XRD)、紫外-可见光分光光度计(UV-Vis)、傅里叶变换红外光谱仪(FT-IR)等对制备的氧化石墨的氧化程度、结构及水洗和不同pH条件对氧化石墨结构的影响进行了分析。实验结果表明,高温退火法可以制备出优质的氧化石墨烯。水洗过程中氧化石墨烯的结构发生了变化而且弱碱性条件下氧化石墨的剥离效果更佳。     

焙烧温度对Ce0.65Zr0.35O2储氧材料性能的影响

用共沉淀法制备了Ce0.65Zr0.35O2氧化物,对不同温度处理后的样品进行了XRD、Raman、BET和储氧量(OSC)的表征.并考察了不同温度焙烧后的氧化物对单钯催化剂三效性能的影响.结果表明,焙烧温度的不同,样品具有不同的织构性能,但该样品的晶相结构稳定,老化前后均为立方相的铈锆固溶体,经1000℃焙烧后未出现相分离,说明该氧化物具有良好的热稳定性能;活性测试结果表明,不同焙烧温度的载体对催化活性影响较大,并以700℃焙烧后的氧化物为载体的催化剂具有最好的三效性能.     

退火温度对硅基溅射银膜微结构和应力的影响

用直流溅射法在硅(111)基底上制备银膜，膜厚为380nm。用BGS6341型电子薄膜应力分布测试仪对膜应力随退火温度的变化进行了研究，结果表明：膜应力随着退火温度的升高而增大，在400℃退火温度下膜应力变化明显。用MXP18AHF型X射线衍射仪测量了膜的衍射谱，对膜微结构随退火温度的变化进行了讨论。制备的Ag膜仍为面心立方结构，呈多晶状态，平均晶粒尺寸为23．63nm，薄膜晶格常数(0．40805nm)比标准样品晶格常数(0．40862nm)稍小。     

氨化温度对氨化Ga2O3/Al膜制备GaN纳米结构材料的影响

采用磁控溅射的方法在Si(111)衬底上溅射沉积了Ga2O3/Al膜,并通过氨化的方法在Si(111)衬底上获得了GaN纳米结构材料,研究了不同的氨化温度对生成GaN纳米结构材料的影响.对样品进行了傅立叶红外吸收(FTIR)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)以及高分辨电镜(HRTEM)测试,分析了不同温度对GaN样品的结构、组分和形貌等特性的影响.结果表明,用该方法在950℃的氨化温度下得到了大量的六方GaN纳米棒.     

Influence of annealing temperature on crystallisation products in Fe75Si10B15 metallic glass

Abstract

Samples of an Fe₇₅Si₁₀B₁₅ metallic glass have been isothermally annealed at 723 and 793 K. At the lower temperature, the crystallisation products consisted of Fe₃Si dendrites and a fine eutectic product while at the higher temperature, an additional phase crystallised from the matrix after approximately 50% transformation. This phase has an orthorhombic structure and has not been reported previously in the Fe–Si–B system. Such variations in crystallisation product may be a feature of many metallic glass systems, but a significant range of annealing temperatures, beyond that usually used for kinetic studies, may be necessary to detect them.

MST/785     

退火温度对SmCo永磁薄膜微结构及磁性能的影响

采用直流磁控溅射法制备SmCo薄膜,研究了退火温度对薄膜微结构及磁性能的影响。XRD分析结果表明,当退火温度为600℃时,SmCo5相析出,而Sm2Co17相在700℃析出。SEM照片可看出,退火温度高于900℃时,六方柱状的SmCo5相和菱方状的Sm2Co17相全部析出。随着退火温度的升高,晶粒尺寸增大,当温度达940℃时,晶粒尺寸减小,而在980℃时,晶粒尺寸又将增大。VSM测试表明,与制备态的薄膜相比,退火后的薄膜在垂直于膜面方向的矫顽力、剩余磁化强度及最大磁能积都增大。960℃时得到矫顽力和剩余磁化强度的最大值,800℃时得到最大磁能积的最大值。     

Effects of annealing on magnetic properties of Fe78B13Si9

We have annealed amorphous Fe₇₈B₁₃Si₉ samples at temperaturesT _a = 355 to 460 ° C for timet _a = 10 to 60 min, in an atmosphere with purging of nitrogen gas. After thermal treatment, we examined the hysteresis loop, DSC curve, and the X-ray diffractogram of each sample. The coercivityH _c, the peak inductionB _max, and the lossW _h were analysed to study the affects of annealing. Stress-relief and partial crystallization are two important parameters in determining optimal annealing conditions.     

Influence of concentration and annealing temperature on spin-coated metal oxide thin films for optoelectronic devices

Journal of Materials Science: Materials in Electronics - The metal oxide thin films, such as cadmium oxide (CdO) and zinc oxide (ZnO) thin films, were deposited by sol–gel-derived spin...     

热退火对低温分子束外延GaAs材料深中心的影响

利用光致瞬态电流谱（Ｏｐｔｉｃａｌ Ｔｒａｎｓｉｅｎｔ ＣｕｒｒｅｎｔＳｐｅｃｔｒｕｍＯＴＣＳ）研究了热退火对低温分子束外延ＧａＡｓ材料深中心的影响,实验结果表明原生和退火的ＬＴ－ＧａＡｓ中都存在三个主要的深中心ＬＴ１、ＬＴ２、ＬＴ２,退火后各峰的相对强度变化很大,特另ＩＬＴ１／ＩＬＴ３＝Ｃ由退火前的Ｃ〉〉１到退火后Ｃ〈〈１,退火温度越高,Ｃ值越小,这主要归因于热退火过程中砷的集聚与沉淀致使与砷反     

Tensile strained Ge quantum wells on Si substrate: Post-growth annealing versus low temperature re-growth

We investigate tensile strained Ge/Si_1 − xGe_x (x = 0.87) multiple quantum wells (MQW) on a Ge virtual substrate abruptly grown on Si for integration in CMOS technology. Two schemes are discussed – Scheme A in situ growth of the MQW stack combined with post-growth rapid thermal annealing (RTA) and Scheme B re-growth of the MQW stack on an RTA strain optimized Ge-VS. Samples are characterized by Raman spectroscopy, X-ray diffraction (XRD), scanning transmission electron microscopy, Brewster transmission and photo-reflectance spectroscopy. The strain in the as-grown virtual substrate of Scheme A, measured with Raman spectroscopy and XRD, increases from 0.17% to 0.24% after RTA to 850 °C. XRD reveals an activated inter-diffusion of the MQWs and, at the highest temperatures (T_RTA > 750 °C), a structural relaxation. The MQWs of Scheme B appear to be of inferior quality. The inter-band transitions in this material are comparatively blue shifted and broad, which is attributed to relaxation induced dislocations at the interface between the virtual substrate and the multiple quantum wells.     

Effects of annealing temperature on microstructure and electrical properties of Mn-Co-Ni-O thin films

Mn_1.85Co_0.3Ni_0.85O₄ (MCN) thin films were prepared on Al₂O₃ substrates by chemical solution deposition method at different annealing temperature (650, 700, 750 and 800 °C). Effects of annealing temperature on microstructure and electrical properties of MCN thin films were investigated. The MCN thin film annealed at 750 °C is of good crystallization and compact surface. It shows lower resistance (4.8 MΩ) and higher sensitivity (3720.6 K) than those of other prepared films. It also has small aging coefficient (3.7%) after aging at 150 °C for 360 h. The advantages of good properties make MCN thin film very promising for integrated devices.     

Effects of annealing temperature on the structure and photoluminescence properties of ZnO films

Zinc oxide (ZnO) films with c-orientation were deposited on Si (1 1 1) substrates at room temperature (RT) by RF-magnetron sputtering. Violet (394 and 412 nm) and green (560 and 588 nm) photoluminescence (PL) were observed from the as-deposited and annealed samples. The PL intensity was increasing with increasing annealing temperature (T_a). The 412 nm violet peak shifted from 412 to 407 nm and the 394 nm violet peak shifted from 394 to 399 nm on increasing the temperature from 500 to 900 °C, whereas no shift in PL green peaks was observed over the whole range of temperature examined. The 412 nm violet luminescence is ascribed to radiative defects related to the interface traps existing at grain boundaries. With the increase of T_a, the stress in the films changed from compressive to tensile, which is believed to have resulted in the observed 412 nm violet emission peak shifts from 412-407 nm. The 394 nm violet luminescence observed is attributed to free excitonic emission, and the increase of the crystal size may result in the 394 nm violet emission peak shifts from 394 to 399 nm. The other two PL bands located at 560 and 588 nm are attributed to oxygen deficiency.     

退火温度对PLT铁电薄膜微结构和电畴的影响

常温下采用射频磁控溅射技术在Pt/TI/SiO2/Si(100)基片上淀积(Pb0.9La0.1)TiO3薄膜,分别在550℃、570℃、600℃、630℃退火1h.采用X射线衍射、原子力显微镜和压电响应力显微镜检测不同退火温度的薄膜,讨论退火温度对薄膜结构、表面形貌和电畴结构的影响.结果表明:随着退火温度的升高,薄膜中钙钛矿相的含量增多,表面粗糙度和颗粒尺寸不断增大,薄膜从无畴状态变为以90°畴为主的多畴,而在退火升降温过程中,由于应力的影响,面外畴更多为取向向下的负畴.     

Effect of sputtering pressure and annealing temperature on the properties of indium tin oxide thin films

Indium tin oxide (ITO) thin films were deposited on glass substrates by RF sputtering system at different sputtering pressure (SP) (20–34 mTorr) and room temperature. The sputtering pressure effects on the deposition rate, electro-optical and structural properties of the as-deposited films were systematically investigated. The optimum sputtering pressure of 27 mTorr, giving a good compromise between electrical conductivity and optical transmittance was found to deposit films. The films were heat-treated in vacuum (200–450 °C) and their electro-optical and structural properties investigated with temperature. A criterion factor Q, which is the ratio between the normalized average transmission to normalized resistivity was defined. It has been observed that Q has its maximum value for heat treatment at 400 °C and the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis proves the films have preferred crystal growth towards (2 2 2) direction and average size of grains are 35–40 nm.     

Effects of 4He substitution on low temperature heat capacities of 2D 3He adsorbed on graphite

No Heading We measured heat capacities of the second layer ³He admixed with a small amount of ⁴He (= 0.9 nm^–2) on graphite preplated with a monolayer ⁴He. The aim of this study is to elucidate possible ⁴He substitution effects on a recently proposed new quantum phase existing at densities just below that (_4/7) for the 4/7 registered phase. This phase is supposed to be the hole (zero-point vacancy) doped Mott localized phase. The substitution gives rise to an excess heat capacity (C_ex) with unusual temperature and density dependencies which is most pronounced at a slightly lower density than _4/7. The C_ex stays relatively large even at _4/7, and suddenly disappears at a slightly higher density. One possible scenario, which is consistent with the present data, is that the C_ex comes from the isotopic mixing effect existing in a narrow density range around _4/7 and that there exists an excess particle phase just above _4/7 in addition to the hole doped phase below. The result may suggest finite fluidity or unexpectedly large band widths for the isotopic impurities in the 4/7 phase.PACS numbers: 67.70.+n, 67.55.–s, 71.10.Ay.