SiO2 Glass Substrates Research Articles

Tunable Localized-Surface-Plasmon-Resonance Characteristics of Independently Prepared Ag-TiO2 Particles

Ag and TiO2 particles prepared by the evaporation-condensation method and spray pyrolysis, respectively, were mixed in N2 gas flow, and then deposited on the SiO2 glass substrate to form a film. Optical properties of the film thus obtained were evaluated using UV-Visible spectrophotometer and Z-scan technique. As a result, the absorption peak wavelength of Ag particles due to localized surface plasmon resonance (LSPR) was shifted toward longer wavelength side with increasing the concentration of Ti(OC3H7)4 used as a starting material of TiO2 particles. This indicates that LSPR peak of Ag particles is strongly influenced by TiO2 particles. Therefore, this method is useful to develop tunable LSPR devices such as optical switches and sensors. Meanwhile, nonlinear refractive index determined by Z-scan technique was negative. [DOI: 10.1380/ejssnt.2006.566]

Preparation of KNbO3 Thin Film by Self-Assembly of Perovskite Nanosheet

Potassium niobate thin films with a perovskite structure were prepared by a new nanosheet self-assembly technique on a SiO2 glass substrate. A homogeneous nanosheet precursor solution was obtained by dissolving layered perovskite K2NbO3F in water at room temperature without any modifier. It was confirmed by X-ray diffraction that the films have a pseudocubic perovskite structure and show continuous transformation from layered perovskite K2NbO3F to perovskite KNbO3. The ultraviolet-visible absorption spectra of the films showed an increase in absorbance with the thickness of thin films, suggesting the growth of a self-assembled multilayer consisting of perovskite nanosheets and K+ ions.

Co – Pt ∕ Pt thin films with perpendicular magnetization and a high coercivity prepared by gas flow sputtering

Pt underlayers were deposited on an SiO2 glass substrate by magnetron sputtering, and then Co–Pt alloy films were deposited on them at 50 °C by gas flow sputtering. Perpendicular magnetization was realized at a composition ranging from 0 to 55 at % Pt. Their structure and magnetic properties were studied as a function of Pt content and annealing temperature from 200 to 400 °C. For as-sputtered Co–Pt(30nm)∕Pt(200nm) films, it was found that the perpendicular coercivity increased with increase in Pt content and had a maximum value of 4.7 kOe at 25 at % Pt. At this composition, the perpendicular anisotropy constant was 1.8×106erg∕cc. Post-annealing of the films in an Ar atmosphere resulted in increases in both coercivity and anisotropy constant. At 300 °C, they reached maximum values of 7.0 kOe and 4.0×106erg∕cc, respectively.

Chemical vapor deposition of tantalum nitride with tert-butylimino tris(diethylamino) tantalum and atomic hydrogen

X-ray photoelectron spectroscopy (XPS) has been used to study the reaction of tert-butylimino tris(diethylamino) tantalum (TBTDET) with atomic hydrogen on SiO2 and organosilicate glass (OSG) substrates. The results on both substrates indicate that, at 300 K, TBTDET partially dissociates, forming Ta–O bonds with some precursor still attached. Subsequent bombardment with atomic hydrogen at 500 K results in stoichiometric TaN formation, with a Ta(4f7/2) feature at binding energy 23.2 eV and N(1s) at 396.6 eV, leading to a TaN phase bonded to the substrate by Ta–O interactions. Subsequent depositions of the precursor on the reacted layer on SiO2 and OSG followed by atomic hydrogen bombardment result in increased TaN formation. These results indicate that TBTDET and atomic hydrogen may form the basis for a low-temperature atomic layer deposition (ALD) process for the formation of ultraconformal TaNx or Ru/TaNx barriers.

Investigations of MgF2 Optical Thin Films Prepared from Autoclaved Sol

MgF2 thin films with ultra low refractive indices were obtained by sol–gel method using sols prepared from magnesium acetate and hydrofluoric acid. The sols were autoclaved in a Teflon cell at 100–180°C for 24 h and then coated on SiO2 glass or CaF2 crystal substrates by spin coating. Subsequently, the samples were heat treated at 150°C for 1 h. The optical properties of the thin films, such as refractive index and transmittance, were investigated in the UV region, especially in the deep UV (DUV, below 250 nm) region. Though the coatings consist of single layers, both samples exhibited high transmittance. In addition, they exhibit such antireflection effect over a very wide range of wavelength. Such a good antireflection effect was produced only by low refractive indices. It has also been confirmed that, even in the range of vacuum UV (VUV, 200–150 nm), CaF2 samples with antireflection coatings could keep such a good antireflection effect.

Growth of FeRh thin films and magnetic properties of FePt/FeRh bilayers

A method for growing the FeRh thin films with a good (001) texture on fused silica (SiO2-glass) substrates is presented. Seed layers of Fe/Ir and the substrate temperature as low as 200°C, at which FeRh is deposited, are effective for growing the Ir-substituted FeRh films with a good (001) texture, though annealing is necessary after deposition. Furthermore, a FePt layer was deposited onto the Fe(Rh,Ir) and perpendicularly magnetized FePt film with (001)-texture was fabricated.

(100)‐Orientation of Pseudocubic Perovskite‐Type LaNiO3 Thin Films on Glass Substrates via the Sol–Gel Process

(100)‐oriented, perovskite‐type LaNiO3 thin films were prepared on SiO2 glass substrates by the sol–gel method. Effects of thermal processing on the orientation, surface morphology, and electrical properties of the films were investigated. The nearly complete (100)‐orientation was achieved by drying the films at temperatures above 350°C before a final heat treatment at 700°C. It was the key to heat the substrate from the other side to obtain the oriented films. A possible mechanism of the orientation is proposed on the basis of surface energies of the films and the substrates and the interfacial energy between them.

Characteristics of oriented LaNiO3 thin films fabricated by the sol–gel method

We fabricated LaNiO3 (LNO) thin films on SiO2 glass, (100) SrTiO3 (STO), (100) Si and CeO2-covered (100) Si substrates by the sol–gel method. The deposited films were heat-treated at 700°C with various conditions, duration and atmosphere. Preferentially (100)-oriented, polycrystalline LNO films were obtained on STO and Si. It was also found that orientated films could be formed even on SiO2 glass and CeO2-covered (100) Si substrates by altering the heating process. We investigated a relationship between the resistance and the crystallite size of the LNO films. The sheet resistance of LNO decreased with increasing crystallite size of LNO. The resistivity and sheet resistance of LNO/STO at 300 K were 340 μΩ·cm and 33.8 Ω/□, respectively, and those values of LNO/CeO2/Si at 300 K were 460 μΩ·cm and 28.8 Ω/□.

Deep-UV Transparent Conductive β-Ga2O3 Film

ABSTRACTDeep ultraviolet transparent and electrical conductive β-Ga2O3 film was prepared on SiO2 glass substrate. The film had electric conductivity of 1 Scm−1, carrier density of 1.4 × 1019cm−3 and mobility of 0.44 cm2V−1s−1. Internal transmittance at wavelength of 248 nm exceeded 50 %. Conductivity was enhanced at an oxygen pressure less than 10−4 Pa, and transparency appeared at a substrate temperature over 800 °C.

Thermoelectric Properties of B12+xC3-x Thin Films Prepared by Pulsed Ion-Beam Evaporation

AbstractThin films of boron carbide (B12+xC3-x) were prepared on glass substrates by a pulsed ion-beam evaporation method. A pulsed proton beam with an energy of 1 MV (peak) and a current of 60 kA was focused on sintered B12+xC3-x targets. Ablation plasma was formed from the irradiated targets and thin films were prepared on Pyrex and SiO2 glass substrates at room temperature. From results of X-ray diffraction, the thin films consisted of a B12+xC3-x phase. Using a known relationship between the composition and the lattice parameters, the composition of B12+x1C3-x thin films was estimated to be x = 0.3 and 1.0, which were close to the nominal composition of the targets. These results indicate that B12+x1C3-x with different carbon contents has been successfully prepared by IBE without substrate heating or sample annealing. Thermoelectric properties of the thin films were measured. A B12+x1C3-x thin film with estimated composition of x =0.9 exhibited the highest power factor at room temperature among the B12+x1C3-x samples reported.

Observation of the crystal-field splitting related to the Mn-3d bands in spinel-LiMn2O4 films by optical absorption

Mn 3d bands in spinel-LiMn2O4 films, synthesized on SiO2-glass substrates by a sol-gel method, were studied using an optical absorption method. Two absorption peaks were observed at around 1.63 and 2.00 eV at room temperature. These peaks were associated with two d–d transitions: One is the Mn t2g to the lower Mn eg bands transition and the other the Mn t2g to the upper Mn eg bands one. A large absorption was also observed above 3.0 eV, indicating a transition from the O 2p valence band to the Mn 3d bands. The d–d transitions showed the blueshifts of 20–30 meV at 77 K comparing with those at room temperature. The observed electronic structure was consistent with the calculated one.

Deposition of highly oriented Bi 12 SiO 20 thin films on Y-stabilized zirconia and SiO 2 by pulsed-laser deposition

We describe the deposition and characterization of Bi12SiO20 (bismuth silicon oxide; BSO) thin films on Y-stabilized zirconia (YSZ) and SiO2 glass substrates by pulsed-laser deposition (PLD) for the application of an electric field sensor. It was found that all films deposited on YSZ substrates heated at 400 °C and more were crystallized and the (310) plane was perpendicular to the substrate normal. The highly (310) oriented crystallized films were even deposited on SiO2 glass substrates, and this will make it possible to grow the crystallized films on the end surface of a SiO2 glass fiber.

Low-Temperature Crystallization of TiO2 Films on Arranged Mono-Layers by Sol-Gel Method

TiO2 gel films were deposited on self-assembled monolayers (SAMs) of octadecy ltrichlorosilane (OTS) and SiO2 glass substrates using Ti(OC3H7 i )4-derived titania sols. It was found that OTS SAM induces precipitation of anatase phase at a rather low temperature of 200°C when a molar ratio of H2O/Ti(OC3H7 i )4 was as low as 0.5 for sol preparation.

Noise-induced local heatings in microbeam analysis

Heatings produced by the irradiation with light ion microbeams were measured in situ by using microthermocouples deposited and etched onto a SiO2 glass substrate. For a given distance r between the microbeam centre and the thermocouple, we show that the heating averaged over the irradiation time decreases as 1/r, in agreement with theory. Moreover, we report strong heating random fluctuations close to the beam resulting from the fluctuations of the beam intensity. We show that, close to the beam, these heating fluctuations dominate largely over the averaged heating, as predicted by the theory of heat propagation with a random source.

On The Formation Of Diffusion Layer Between Cr Film And Glass

Abstract Chromium films are commonly used as a metal “glue” layer because of good adhesion to glass. It is believed that an intermediate oxide layer is formed during deposition, since Cr has a very strong affinity for oxygen. For example, a graded Cu/Cr/CrOx/SiO2 structure ensures excellent adhesion of Cu to glass, whereas Cu exhibits poor adhesion to most dielectrics. In our recent study, however, a diffusion layer, Cr2O3+SiOy, was observed between CrOx and SiO2 (glass) substrate. It is quite likely that this diffusion layer is responsible for the good adhesion of Cr film to glass. The relative compositions of the major components across the interface are shown in Fig 1. A Cr film was evaporated on Corning Code 1737 glass (Al2O3-B2O3-SiO2 with ˜67at.% Si02) substrate at room temperature (RT) and subsequently covered with about lOnm Cu. A 5nm'wide diffusion layer is seen. The corresponding regions are also indicated in Fig 2, an Annular Dark Field (ADF) image whose contrast is approximately proportional to the density if the thickness is assumed uniform.

Enhancement of polymerization in CH3SiO3/2 coating film by gaseous amines

Coating films of CH3SiO3/2 on sapphire, SiO2 glass, and metallic substrates have been prepared from an aluminium acetylacetonate catalyzed oligomer solution. The coating films are treated in atmospheres of gaseous amines. The reaction is monitored by using an infrared absorption of SiOH at 3000–3700 cm−1. The polymerization of silanols in the coating films proceeds at an elevated treatment temperature. The degree of polymerization becomes larger with the exposure to amines, indicative of a catalytic effect of gaseous amines on the polymerization.

Pulsed Laser Deposition of Low-Resistivity Indium Tin Oxide Thin Films at Low Substrate Temperature

Indium tin oxide (ITO) thin films were grown on SiO2 glass and silicon (Si) substrates from a 95 wt% In2O3–5 wt% SnO2 sintered ceramic target by pulsed laser deposition (PLD). The films were deposited under different oxygen pressures (Po2) of 5×10-3 to 5×10-2 Torr at room temperature (RT) and 200°C. Po2 was found to have a critical influence on the optical and the electrical properties of the ITO films. Under a Po2 of 1×10-2 Torr, ITO films with resistivity as low as 4.5×10-4 and 1.8×10-4 Ωcm were obtained on glass at RT and 200°C, respectively. Moreover, by increasing the substrate temperature (Ts) to 350°C, the resistivity was further reduced to 1.3×10-4 Ωcm. Optical transmittance in visible light greater than 85% was attained in all the films deposited under Po2 above 5× 10-3 Torr. However, a reduction in the transmittance to less than 80% was observed as Po2 decreased. The films deposited at RT were amorphous, whereas those produced at 200°C were polycrystalline.

Probing overheatings under microprobe irradiation via Zn vaporisation

A thin layer of ZnO0.3 deposited on a SiO2 glass substrate was irradiated with a 2 MeV α microbeam. The disappearance of ZnO0.3 in the neighbourhood of the beam was registered in situ. We quantitatively account for this behaviour in the framework of a very simple vaporisation model based both upon the local temperature increase resulting from the microbeam itself and upon the variation of the Zn vapour pressure with the local temperature. Other possible explanations are briefly discussed.

SrCu 2 O 2 : A p-type conductive oxide with wide band gap

SrCu 2 O 2 thin films were prepared on SiO2 glass substrates by pulsed laser deposition. The film deposited in O2 atmosphere of 7×10−4 Pa at 573 K showed high optical transmission in visible and near-infrared regions. Potassium was doped at Sr site for substitutional doping. The optical band gap of the K-doped film was estimated to be ∼3.3 eV. The dc electrical conductivity of the K-doped film at 300 K was 4.8×10−2 S cm−1 and the activation energy was 0.10 eV. Positive sign of Seebeck and Hall coefficients demonstrated the p-type conduction of the film. Hole concentration and mobility at 300 K were 6.1×1017 cm−3 and 0.46 cm2 V−1 s−1, respectively.

Growth of polycrystalline hexagonal-close-packed Co films on glass substrates from low kinetic energy vapor

For the first time it has been demonstrated that polycrystalline Co films (10–300 nm) of hcp single phase can be produced on SiO2 glass substrates by a gas-flow-sputtering technique. The hcp Co films are obtained at substrate temperatures below 620 K and fcc Co films are obtained above 720 K. A mixture of hcp and fcc phases is formed between these temperatures. Gas-flow-sputtering allows the sputter deposition at high pressure in the range of 1 Torr, where sputtered particles are thermalized to the temperature of the sputtering gas; the deposition of such low kinetic energy vapor can be attributable to the formation of hcp phase for Co films.