Growth and Characterization of Pulsed-Laser-Deposited Ilmenite–Hematite Thin Films

The ilmenite–hematite (1 − x) FeTiO₃ · xFe₂O₃ solid solution system is considered to be a novel material for spin-electronics, microelectronics, high-temperature electronics, and radhard electronics. This paper focuses on thin films of composition x = 0.33 grown on (100) MgO single-crystal substrates using pulsed-laser deposition (PLD) under different argon–oxygen mixtures. The surface of the MgO was found to possess MgO₂ crystals, yielding an orientation relationship, [001] MgO ∥ [011] MgO₂ and (00)MgO ∥ (10) MgO₂. The structural characterizations show that the films are crystalline and homogeneous without any secondary phase. The films show a weak and inclined (110) growth epitaxy. A bandgap of 3.4–3.7 eV was obtained for these films from optical measurements carried out in the UV–visible region. Electrical measurements confirmed the semiconducting behavior. However, the resistivity was found to increase substantially on the slightest addition of oxygen into the chamber.     

Specific Features of Vapor–Liquid–Solid Nanostructure Growth on the Surface of SnS Films during Plasma Treatment

The formation of nanostructure arrays on the surface of nanocrystalline tin sulfide (SnS) films during inductively coupled argon plasma treatment is investigated. The parameters of the nanostructures are studied by electron microscopy and energy-dispersive X-ray microanalysis and the main regularities of nanostructure growth are established. It is shown that the SnS nanostructure growth during plasma treatment is complex and involves the vapor–liquid–solid mechanism with self-assembled tin seeds.     

Growth Front Evolution of GaN Thin Films on Sapphire Substrate During HVPE

The growth front evolution of GaN thin films deposited on sapphire substrate by hydride vapor phase epitaxity has been studied with atomic force microscope. The evolution of the surface morphology presents four features of stage with the growth process. In initial growth stage, the surface is granular, and the typical grain diameter is about 250nm for t =0.1min. 3D growth plays a key role before the films come up to full coalescence, which causes a rough surface. After 0.1min the growth dimension decreases with the increase of lateral over growth, the surface roughness obviously decreases. From 0.4min to 3min, the growth front roughness increases gradually, and the evolution of the surface roughness exhibits the characteristics of self-affined fractal. Beyond 3min, the root-mean-square decreases gradually, which means the deposition behavior from hyper-2D growth gradually turns into layer growth mode with the increase of growth time.     

AFM and XPS Study on the Surface and Interface States of CuPc and SiO2 Films

利用热生长工艺和热蒸发方法分别获得CuPc和SiO2薄膜层,通过原子力显微镜和X射线光电子能谱对其表面界面电子状态进行了研究,并采用高斯拟合方法对各谱进行了详细分析.结果表明,在氧原子的作用下,N1s,C1s,O1s 和Cu2p都经受了一定的化学位移,从而使得各原子间的相互作用强度有所改变,这是导致OFET性能劣化的重要原因之一.对OFET而言,采用溅射工艺制备的SiO2层应比热氧化生长的SiO2层更合适.     

Epitaxial Growth of Bi-2201 and 2212 Thin Films by Magnetron Sputering

ＥｐｉｔａｘｉａｌＧｒｏｗｔｈｏｆＢｉ２２０１ａｎｄ２２１２ＴｈｉｎＦｉｌｍｓｂｙＭａｇｎｅｔｒｏｎＳｐｕｔｅｒｉｎｇＹ．Ｚ．ＺｈａｎｇＤ．Ｇ．ＹａｎｇＬ．ＬｉＢ．Ｒ．ＺｈａｏＨ．ＣｈｅｎＣ．ＤｏｎｇＨ．Ｊ．ＴａｏＨ．Ｔ．ＹａｎｇＪ．Ｗ．ＬｉＢ．Ｙ...     

Dielectric Spectroscopy and Features of the Mechanism of the Semiconductor–Metal Phase Transition in VO2 Films

Semiconductors - In the range of 0.1–106 Hz, the temperature-induced transformation of the frequency dependences of the dielectric-loss tangent tanδ(f) as well as the Cole–Cole...     

Electron Microscopy Study of Ferroelectric Memory Based on Si–SiO2–Ti–Pt–PZT Multilayer Structure

Model Si–SiO₂–Ti–Pt–PZT multilayer structures obtained by chemical solution deposition at excessive (relative to the stoichiometric composition) amounts of lead in the starting film-forming solution (x= 0–30 mol %) were studied by TEM and X-ray microanalysis techniques. In the absence of excessive lead, the films crystallize largely into the metastable phase of pyrochlore, which does not have ferroelectric properties. With an excessive amount of lead added, PZT ceramic crystallizes into the ferroelectric phase of perovskite and has columnar grains 0.2 m in size. The thermal stability of the metallization system during the formation of the ferroelectric film was investigated. A 180-nm-thick transition layer between the Pt electrode and the adhesive titanium film was discovered. This layer, resulting from high-temperature synthesis, consists of fine-grain platinum, as well as metal oxides and silicides.     

Influence of Nanocrystallization on Magnetic Properties of the Co-Based Alloys Thin Films

Since Yoshizawa et al found iron-basednanocrystalline soft magnetic materials in 1988[1],nanocrystalline soft magnetic thin films have attractedmuch attention due to their wide applications.According to the random anisotropy model proposedby Herzer[2,3], as grain size is smaller than theexchange correlation length, coercivity andpermeability will be proportional and inverselyproportional to the grain size to sixth power,respectively. Therefore, in order to reach excellent softmagnetic properti…     

Optical and Electrical Properties of Polyimide Thin Films Doped-Cu-phthalocyanine Polymerized by Vapor Phase Deposition

Using Cu-phthalocyanine(CuPc),4,4’-diaminodiphenyl ether and pyromellitic dianhydride as monomer materials, polyimide(PI) thin films doped-CuPc have been prepared onto glass substrate by vapor phase co-deposition polymerization under a vacuum of 2×10~(-3)Pa and thermal curing of polyamic acid film in at temperature of 150-200℃ for 60min. In this process, the polymerization can be carried out through controlling the stoichiometric ratio, heating time and deposition rates of the three monomers. IR spectrum identifies the designed chemical structure of the polymer. The absorption of polyimide doped-CuPc is very intense in vis-range and near-infrared by UV-Vis spectrum. And, the PI films doped-CuPc polymerized by vapor phase deposition have uniformity, fine thermal stability and good nonlinear optical properties, and the third-order optical nonlinear susceptibility χ~((3)) with degenerate four-wave mixing can be 1.984×10~(-9)ESU.     

Formation of Planar Field-Emission Devices Based on Carbon Nanotubes on Co–Nb–N–(O) Alloy

Semiconductors - Integrated field-emission devices and integrated circuits (ICs) based on them are a promising direction in microelectronics, which is associated with the use of low-voltage and...     

Formation of GaN Nanowires by Ammoniating Ga2O3 Films Deposited on Oxidized Al Layers on Si Substrate

Large quantities of gallium nitride（GaN） nanowires have been prepared via ammoniating the Ga2O3 films deposited on the oxidized aluminum layer at 950℃ in a quartz tube. The nanowires have been confirmed as crystalline wurtzite GaN by X-ray diffraction, X-ray photoelectron spectrometry scanning electron microscope and selected-area electron diffraction. Transmission electron microscope （TEM） and scanning electron microscopy（SEM） reveal that the nanowires are amorphous and irregular, with diameters ranging from 30 nm to 80 nm and lengths up to tens of microns. Selected-area electron diffraction indicates that the nanowire with the hexagonal wurtzite structure is the single crystalline. The growth mechanism is discussed briefly.     

An Apparatus for the Production and Ion Bombardment of Thin Films†

This communication describes a versatile apparatus for the production of thin polycrystalline metallic films under conditions of high purity. The apparatus includes facilities for film preparation by evaporation and cathodic sputtering and for ion bombardment of the films under the same conditions of purity as obtained during preparation. The films can also be annealed before and after ion bombardment, although at this stage of the programme these facilities have not been fully used. Electrical conductivity measurements of the films can be made in situ and some preliminary data on the effects of ion bombardment on the electrical conductivity of thin metallic films are reported.     

Ag Doping Effects on the Microstructure,Morphology, Optical,and Luminescence Properties of Sol–Gel-Deposited ZnO Thin Films

Semiconductors - A sol–gel dip-coating process is used to prepare highly c-axis-oriented thin films of zinc oxide (ZnO) on glass substrates. The effects of moderate Ag doping (Ag:Zn <...     

The Hall and Seebeck Effects in Bismuth Thin Films on Mica Substrates in the Temperature Range of 77–300 K

Semiconductors - The effects of film thickness and block size on the Hall and Seebeck effects in bismuth films on mica substrates are analyzed using experimental data. A preferential decrease in...     

Growth of SiGe Films by Cold-wall UHV/CVD Using GeH4 and Si2H6

An ultrahigh vacuum chemical vapor deposition (UHV/CVD) system is introduced.SiGe alloys and SiGe/Si multiple quantum wells (MQWs) have been grown by cold-wall UHV/CVD using disilane(Si2H6) and germane (GeH4) as the reactant gases on Si(100) substrates.The growth rate and Ge contents in SiGe alloys are studied at different temperature and different gas flow.The growth rate of SiGe alloy is decreased with the increase of GeH4 flow at high temperature.X-ray diffraction measurement shows that SiGe/Si MQWs have good crystallinity,sharp interface and uniformity.No dislocation is found in the observation of transmission electron microscopy(TEM) of SiGe/Si MQWs.The average deviation of the thickness and the fraction of Ge in single SiGe alloy sample are 3.31% and 2.01%, respectively.     

Evolution of Structural,Optical and Electrical Characteristics of Spin-Coated CdO Thin Films with the Gelation State of the Sol–Gel

The present work is intended to investigate the influence of the gelation state of the sol–gel on the properties of spin-coated cadmium oxide (CdO) thin films. The viscosity of the sol–gel increases at a slow uniform rate up to 5 days (break-off point) after which the rise becomes progressively more rapid and it attains saturation after 10 days of gelation. Films have been grown with gelation times of 2 days, 4 days, 6 days, 8 days, 9 days and 10 days. The visual characteristics of the films have been discussed in terms of the centrifugal force acting on the sol–gel. The sol–gel viscosity seems to be better suited to represent the gelation state of the sol–gel rather than the gelation time. The x-ray diffraction studies show that lower gelation times and lower sol–gel viscosities give rise to single crystalline CdO thin films while gelation times of 6 days and above (i.e. sol–gel viscosities of 2.92 × 10^?3 N s m^?2 and more) yield polycrystalline CdO thin films. The gelation state of the sol–gel has been found to have a strong bearing on the properties of CdO thin films, and highly conducting and transparent CdO thin films can be achieved by controlling the gelation state of the sol–gel and the results obtained have been reported.     

Dielectric Spectroscopy and Mechanism of the Semiconductor–Metal Phase Transition in Doped VO2:Ge and VO2:Mg Films

Semiconductors - The frequency dependences of the dissipation factor tanδ(f) and the Cole–Cole diagrams for germanium- and magnesium-doped vanadium-dioxide films in the range of...     

Effect of the Phase Composition and Local Crystal Structure on the Transport Properties of the ZrO2–Y2O3 and ZrO2–Gd2O3 Solid Solutions

Russian Microelectronics - The results of investigating the crystal structure, ionic conductivity, and local structure of the (ZrO2)1 –x(Gd2O3)x and (ZrO2)1 –x(Y2O3)x (x = 0.04, 0.08,...