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The germanium films were deposited on TiAlN bottom electrode at various temperatures by metal organic chemical vapor deposition using Ge(allyl)4(Ge(C3H5)4) and Sb(iPr)3(Sb(C3H7)3) precursors. Deposition of germanium films was only possible by a catalytic role of Sb metal by a thermal decomposition of Sb(iPr)3(Sb(C3H7)3) precursors. Deposition rate of the Ge films increases with increasing Sb bubbling temperature at a substrate temperature of 370 °C. The deposition characteristics of Ge films were controlled by a surface reaction in the temperature range from 360 to 380 °C and were controlled by a mass transport in the range of 380–400 °C. The step coverage of Ge films in 500×200 nm2 trench structure was approximately 93% at a substrate temperature of 370 °C. [ABSTRACT FROM AUTHOR]

Presents a study which prepared stoichiometric thin films with various thickness on substrates using conventional radio frequency magnetron sputtering method with a ceramic target containing excess BaO and SrO. Experimental details; Results and discussion; Conclusions.

Presents a study which prepared polycrystalline Pb(Zr[subx]Ti[sub1-x])O[sub3] (PZT) thin films on p-type silicon wafers by the metalorganic chemical vapor deposition process. Materials and methods used; Details on the x-ray diffraction and microstructural analyses of PZT thin films with different deposition temperatures; Effect of the compositional ratio between zirconium and titanium on PZT structure.

Presents a study which examined the effect of post heat treatment on the characteristics of SrTiO[sub3] thin films that were deposited on the p-type silicon(100) substrate and annealed in oxygen at various temperatures. Materials and methods; X-ray diffraction patterns of the films; Description of the normalized atomic concentrations of the as-deposited Sr-TiO[sub3] films; Characteristics of the depth profiles of each component for SrTiO[sub3] films.

Presents a study that examined particle size dependence of the dielectric and piezoelectric properties of ceramic-polymer composites. Determination of the thickness of the surface layer of the composites; Calculation of the dielectric constant of the composites; Analysis of the hysteresis loop of the composites.

Investigates the formation of the high-temperature superconducting phase in the bismuth-strontium-calcium-copper-oxygen system by measuring the electrical properties with temperature in an oxygen atmosphere. Temperature dependence of the electrical conductivity; Analysis of X-ray patterns; Results of differential thermal and thermogravimetric analysis.

Surface modification of Li[NiCoMn]O as a cathode material of lithium-ion batteries was carried out by hydrothermal treatment using lithium lanthanum titanate ([Li,La]TiO). The modified surfaces were analyzed by morphology observation using transmission electron microscopy and by element investigation using X-ray photoelectron spectroscopy. It was thereupon found that the [Li,La]TiO-coated layer formed by the surface modification played a definitive role in suppressing the solid electrolyte interface during repeated charge and discharge cycles. In addition, the thermal stability was enhanced by coated layer, resulting in an increase of the onset temperature to occur an exothermic reaction during thermal runaway. [ABSTRACT FROM AUTHOR]

Abstract: A sample of LiMn2O4 spinel oxide was surface-modified with lithium lanthanum titanate ([Li,La]TiO3), which was developed as a lithium ionic conductor, by means of hydrothermal processing and subsequent heat treatment at 400°C. The surface coating layers were analyzed by morphology observation using a transmission electron microscopy. Energy-dispersive spectrometry and X-ray photoelectron spectroscopy were used for element investigation. The surface modification effects on rate capability during cycling and capacity retention for the LiMn2O4 spinel oxide were confirmed. Then Mn dissolution during storage at elevated temperatures of the pristine, coated sample was characterized. The Mn dissolution characterization was based on the idea that Mn dissolution is one of the most significant reasons for capacity loss for LiMn2O4 spinel oxide, and this phenomenon is especially severe at elevated temperatures. Our experimental results indicate that the surface-modified sample shows much a better initial capacity and rate capability compared with the pristine sample. The [Li,La]TiO3 coating effectively enhances the structural stability of LiMn2O4 at elevated temperatures, most likely because the [Li,La]TiO3-modifying layers play a definitive role in suppressing Mn dissolution in the electrolyte during storage. [Copyright &y& Elsevier]

Abstract: This study reports the facile synthesis of highly conductive SrRuO3(SRO)–RuO2 composite nanofibre mats and their potential suitability for application in electrochemical capacitors as an active electrode material. SRO–RuO2/poly(vinyl acetate) composite nanofibre mats are electrospun on to a Au-coated SiO2/Si substrate and a Ti substrate, subsequently thermocompressed at 60°C, and calcined at various temperatures (from 350 to 850°C). The calcined SRO–RuO2 nanofibre mats exhibit porous morphologies and bundle shapes composed of multiple-fibrils with a nanoparticle diameter ranging from 20 to 50nm. Single SRO–RuO2 nanofibre and multiple SRO–RuO2 nanofibre mats show high electrical conductivity of 476 and 40.8Scm−1, respectively. Pseudocapacitors using SRO–RuO2 nanofibre mats calcined at 350°C exhibit a high specific capacitance of 192Fg−1 at a scan rate of 10mVs−1. The superior capacitance retention (83.4%) of the SRO–RuO2 nanofibre mats is maintained even at rapid scan rate of 1000mVs−1. [Copyright &y& Elsevier]

Abstract: Vertically oriented TiO2 nanotube arrays were fabricated by the anodization of pure titanium deposited on silicon substrates. The TiO2 nanotubes were grown by anodization in aqueous-base and glycerol-base electrolytes at different potentials between 5 V and 30 V. Films with homogeneously distributed pores having an average diameter of 100 nm or 40 nm were obtained. The dependences of pore morphology and pore formation rate on process parameters were evaluated. In particular, thickness-conversion ratio from titanium to TiO2 nanotube was presented to compare a growing character in different electrolytes. [Copyright &y& Elsevier]

We assumed that liquid water was mainly composed of two hydrogen-bonded liquid structures between which the transformation occurred resulting in the dynamic equilibrium of them. Implanting the significant liquid structure theory directly to a general thermodynamic expression for the mixture of certain two species, which are in equilibrium with each other, we obtained a partition function for the above water model. Using this method, we could represent two liquid structures of water more explicitly in the partition function compared to the previous work. The number of water molecules (q) in a collective motion (the size of flickering cluster in liquid water) for the transformation between two liquid structures has been difficult to know, and it was estimated in this work by investigating which cases showed Arrhenius type of the transformation. This value was also confirmed by considering the temperature-dependent compressibility of water and it was roughly 10–25 (more exactly 15–20). Using the induced partition function with q=20, various properties of water were calculated and they showed a good agreement with experimental data. Especially, the density maximum at 4 °C was calculated without the parameter fitting intended for it. [Copyright &y& Elsevier]

Water structure around hydrophilic adsorbents is expected to differ from normal water structure. In some cases, a change of water structure seems to significantly affect phenomena involved in water-adsorbent systems. To investigate this, we have performed molecular dynamic simulations of three systems, water between (111) surfaces of Pt, water between (100) surfaces of Pt, and pure water at 298 K. For the analysis of water structure, we concentrated on the five-membered ring (R5) structure and six-membered ring (R6) structure, which are the most probable in nature. For both (111) and (100) of Pt, the ratio of hexameric ring/pentameric ring (R6/R5) in semibound regions was higher than that of bulk water, as expected. The function of adsorbent ceramics was explained in terms of the change of water structure when they are used as biomaterials, support materials, etc. The obscure mechanisms for the effects of medicine stones, antioxidants, etc., were also discussed from this point of view. [Copyright &y& Elsevier]

Ge2Sb2Te5 (GST) films were deposited on TiN(50 nm)/SiO2/Si substrates and trench structures of TiAlN(100 nm)/Si with various deposition parameters by metal organic chemical vapor deposition (MOCVD). Hexagonal GST films were deposited at temperatures of 330–370 °C, deposition pressure of 40 Torr, bubbling temperatures of Ge(50 °C), Sb(10 °C), and Te(30 °C) precursors. Germanium incorporation into GST films by MOCVD is sensitively influenced by deposition parameters such as deposition pressure, deposition temperature, and bubbling temperatures of precursors. Trench structures with a diameter of 120 nm and a height of 200 nm are completely filled by GST MOCVD. [ABSTRACT FROM AUTHOR]

Makes observations on the effect of electric field on the phase transition in zirconium titanate (ZrTiO4) ceramic. Experimental procedures; Effect of the increase of direct current electric field on normal incommensurate phase transition temperature.

Abstract: This work presents a simple and versatile route to produce macroporous p-type metal oxide thin films. Two-dimensional arrays of p-type NiO films with a hollow hemisphere structure were fabricated by colloidal templating and RF-sputtering followed by a subsequent heat treatment. The diameter and shell thickness of the NiO hemisphere were 800nm and 20nm, respectively. X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the pure NiO phase with grain size of 10nm was obtained at calcination temperatures that exceeded 450°C. Close-packed arrays of hollow NiO hemispheres were found to exhibit p-type gas sensing properties against (CO, H2, C3H8, CH4, NO2, and C2H5OH), leading to significantly enhanced responses to C2H5OH (R gas /R air =5.0 at 200ppm). [Copyright &y& Elsevier]

Abstract: The influence of processing parameters on phase formation and particle size of hydrothermally synthesized BiFeO3 powders was investigated. BiFeO3 powder was synthesized by dissolving bismuth nitrate and iron nitrate in KOH solution at temperatures ranging from 150 to 225°C. X-ray diffraction patterns and scanning electron microscopy observation indicated that rod-like α-Bi2O3 phase was formed at initial stage of reaction and dissolved into ions to form thermodynamically stable BiFeO3 phase. Single-phase perovskite BiFeO3 has been formed using a KOH concentration of 8M at a temperature of ≥175°C in a 6h reaction period. BiFeO3 particle growth was promoted by lowering the KOH concentration, or increasing the duration time or reaction temperature. The effects of processing conditions on the formation of crystalline BiFeO3 powders were discussed in terms of a dissolution–precipitation mechanism. The magnetization of the BiFeO3 powders at room temperature showed a weak a ferromagnetic nature. [Copyright &y& Elsevier]

Abstract: We report on high mobility ZnO thin film transistors (TFTs) (<5V), utilizing a room temperature grown MgO–Bi1.5Zn1.0Nb1.5O7 (BZN) composite gate insulator on a glass substrate. 30mol% MgO added BZN composite gate insulators exhibited greatly enhanced leakage current characteristics (~<2×10−8 A/cm2 at 0.3MV/cm) due to the high breakdown strength of MgO, while retaining an appropriate high-k dielectric constant of 32. The ZnO-TFTs with MgO–BZN composite gate insulators showed a high field-effect mobility of 37.2cm2/Vs, a reasonable on–off ratio of 1.54×105, a subthreshold swing of 460mV/dec, and a low threshold voltage of 1.7V. [Copyright &y& Elsevier]

Abstract: LiNi0.8Co0.2O2 is a promising candidate to replace LiCoO2. The present paper describes the preparation of LiNi0.8Co0.2O2 compounds from nitrate sources and sucrose (or sugar) by the sucrose combustion process (SCP), which involves application of a conventional combustion method. In the proposed approach, sucrose serves as a fuel, a dispersing agent, and a precipitation suppressant. Precursors were made via a combustion reaction, and LiNi0.8Co0.2O2 was subsequently synthesized by heat treatment at 800°C for 16h in oxygen atmosphere. The initial discharge capacity was 175mAh/g when a cell was operated at 2.7–4.3V at 0.5C-rate. Furthermore, it shows good cycling stability. When increased amount of sucrose were added as a start material, the final calcined powder displayed smaller particle size and better discharge capacity. It is expected that optimization of the heat treatment conditions would yield LiNi0.8Co0.2O2 with excellent properties. Furthermore, SCP is expected to be applicable to the production of various materials. [Copyright &y& Elsevier]

The authors report on the influence of Mg acceptor doping on the markedly reduced leakage current characteristics (<5×10-8 A/cm2 at 2 MV/cm) of Ba0.6Sr0.4TiO3 thin films. The suitability of room temperature deposited Mg-doped Ba0.6Sr0.4TiO3 films as gate insulators for low-voltage ZnO thin-film transistors (TFTs) (<6 V) was investigated. All room temperature processed ZnO-TFTs on plastic substrates exhibited a high field-effect mobility of 16.3 cm2/V s and a current on/off ratio of 6.4×104. The threshold voltage and subthreshold swing were 2.8 V and 400 mV/decade, respectively. [ABSTRACT FROM AUTHOR]

The authors report on the role of MgO capping layers in notably reducing leakage currents and improving mobility in ZnO thin film transistors (TFTs) utilizing compatible high-k Bi1.5Zn1.0Nb1.5O7 (BZN) gate insulators. All room temperature processed ZnO based TFTs with stacked MgO/BZN gate insulator exhibited a much enhanced field effect mobility of 5.4 cm2/V s with excellent saturation characteristics as compared to that (μFE=1.13 cm2/V s) of ZnO based TFTs with BZN gate insulator. This work demonstrates the suitability of MgO/BZN stacked gate insulators in the fabrication of low voltage ZnO based TFTs on plastic substrates. [ABSTRACT FROM AUTHOR]

Abstract: SnO2 hollow nanofibers (HNFs) with diameters of 300–500nm were fabricated via electrospinning of templating nanofibers and RF-sputtering of SnO2 thin overlayers (15–20nm thick and comparable grain size) followed by heat-treatment at 450°C. Gas sensors using these HNFs exhibited n-type gas sensing characteristics and an enhanced gas response to 2ppm NO2 (R gas /R air =81.4) as compared to that (R gas /R air =19.9) of planar SnO2 thin films. The enhanced response to NO2 is attributed to the greater accessible active area and the greater space charge modulation depth associated with the hollow thin walled structures. [Copyright &y& Elsevier]

Abstract: Highly ordered TiO2 nanotube arrays fabricated by anodization are very attractive to dye-sensitized solar cells (DSCs) due to their superior charge percolation and slower charge recombination. However, the efficiency of TiO2-nanotube-based DSCs is 6.89%, which is still lower than that of TiO2-nanoparticle-based DSCs. We have suggested the transplanting the highly ordered TiO2 nanotube arrays to FTO glass to improve the performance of TiO2-nanotube-based DSCs. DSCs based on transplanted TiO2 nanotube arrays and TiO2 nanoparticles were fabricated by same process and materials to exclude the unexpected factors. In TiO2 thickness of ca. 15μm, the efficiency of 2.91% in front-side illuminated DSCs based on TiO2 nanotube arrays was higher than those in back-side illuminated DSCs based on TiO2 nanotube arrays and in front-side illuminated DSCs based on TiO2 nanoparticle. Front-side illuminated DSCs based on TiO2 nanotube arrays having various thicknesses were successfully fabricated. The efficiency in DSCs having 20.0μm thick TiO2 nanotube arrays was improved to 5.36% by TiCl4 treatment. [ABSTRACT FROM AUTHOR]

Abstract: The BaTiO3–CoFe2O4 (BTO–CFO) composite films were grown on SrTiO3 (STO) (100) substrates at 750°C under various working pressures by pulsed laser deposition. The composite film grew into a supersaturated single phase at the working pressure of 10mTorr, BTO and CFO (00l) oriented hetero-epitaxial films on STO (100) at 100mTorr, and a polycrystalline composite film at 500mTorr. The slow growth rate at high working pressure led to the phase separation in the composite film. The CFO was compressively strained along out-of-plane due to the lattice mismatch with the BTO matrix phase. The BTO–CFO composite film grown at 100mTorr showed reversible switching of ferroelectric polarization and magnetic hysteresis with strong magnetic anisotropy. [Copyright &y& Elsevier]

Abstract: Nanomaterials are attracting a great deal of attention as potentially excellent transporters of peptides, proteins, genes, and drug medications; however, thus far many nanomaterials are toxic in vivo. The nanotubes utilized in the system described herein were controlled so as not to exhibit toxicity, due to their extremely small dimensions and the constituent material itself. A drug delivery system using silica coated titania nanotube–protein conjugations was applied to mouse neural stem cells (m-NSCs) and cultured for one month. Nanotubes were prepared by silica sol–gel treatment and bonded with proteins by an electrical charge and were readily detached from proteins in cytoplasm. The delivered proteins evidenced functions in live cells for transcriptional factors; the morphology of the cells was consequently altered. In this study, we demonstrate the ability of this nano-sized material to deliver peptides, proteins, and drugs, and also show that the delivered proteins continued to function in live cells. [Copyright &y& Elsevier]

Abstract: Epitaxial MgFe2O4 (MFO) thin films have been deposited on SrTiO3 (STO) (100) substrates via a pulsed laser deposition technique under different oxygen partial pressures at 650°C. The various oxygen partial pressures showed significant influence on the sticking coefficient and the spatial distribution of target materials. The lattice constant of the MFO thin films was decreased with increasing an oxygen partial pressure. The thin films synthesized at high oxygen partial pressure showed rough surface morphology. Also, epitaxial MFO thin films showed anisotropic magnetic behavior and the film grown at the oxygen pressure of 40mTorr exhibited the highest saturation magnetization of 194emu/cc. [Copyright &y& Elsevier]

Abstract: The effects of Fe doping on phase stability and electrical conductivity were investigated for the 25mol% Sr and 20mol% Mg-doped lanthanum gallates (LSGM-2520). While secondary phases, in addition to perovskite phase, were formed for an undoped LSGM-2520 in accordance with previous reports, a single phase perovskite phase was obtained by addition of a small amount (∼4mol%) of Fe to LSGM-2520. The conductivity of 4mol% Fe-doped LSGM-2520 was as high as 0.17Scm−1 at 800°C and it was confirmed to be ionic based on its dependency on oxygen partial pressures. Crystallographic analysis using neutron diffraction and electron diffraction determined the crystal structure and lattice parameters for 4mol% Fe-doped LSGM-2520. [Copyright &y& Elsevier]

Abstract: A mixed cathode material between Li2MnO3 and Li[Mn1/3Ni1/3Co1/3]O2 for high capacity lithium secondary batteries was introduced in this study. It was prepared using the sucrose combustion process because this is a simple process. The oxidation states of Mn, Co and Ni ions in the pristine Li[Li(1−x)/3Mn(2−x)/3Ni x/3Co x/3]O2 compounds were confirmed to be tetravalent, trivalent and divalent, respectively, via XANES measurements. Electrochemical charge/discharge studies showed that the highest first discharge capacity of 224mAh/g was obtained in composition of x =0.5 at a 0.2C rate. The oxidation state of the Co and Ni ions in the Li[Li1/6Mn1/2Ni1/6Co1/6]O2 changed to higher oxidation states, but that of the Mn ions did not change. [Copyright &y& Elsevier]

Recently, there have been many reports on efforts to improve the rate capability and discharge capacity of lithium secondary batteries in order to facilitate their use for hybrid electric vehicles and electric power tools. In the present work, we present a ZrO2-coated Li[Li1/6Mn1/2Co1/6Ni1/6]O2. The bare Li[Li1/6Mn1/2Co1/6Ni1/6]O2 shows a high initial discharge capacity of 224 mAh g−1 at a 0.2 C rate. Owing to the stability of ZrO2, it was possible to enhance the rate capability and cyclability. After 1 wt% ZrO2 coating, the ZrO2-coated Li[Li1/6Mn1/2Co1/6Ni1/6]O2 showed a high discharge capacity of 115 mAh g−1 after 50 cycles under a 6 C rate, whereas the bare Li[Li1/6Mn1/2Co1/6Ni1/6]O2 showed a discharge capacity of only 40 mAh g−1 and very poor cyclability under the same conditions. Based on results of XRD and EIS measurements, it was found that the ZrO2 suppressed impedance growth at the interface between the electrodes and electrolyte and prevented collapse of the layered hexagonal structure. [ABSTRACT FROM AUTHOR]

Abstract: Nanostructured semiconducting metal-oxides and particularly one-dimensional nanotube devices offer enhanced energy conversion efficiencies in dye-sensitized solar cells (DSSCs). To absorb a sufficient light, the thickness and surface area of TiO2 photoelectrode are important. We focus on the preparation of transparent TiO2 nanotube photoelectrode grown perpendicularly on a conductive glass substrate. For growing nanotube array using anodization method, deposition of high-quality titanium is needed. We could obtain relatively longer 680-nm-thick TiO2 nanotube arrays in glycerol-based electrolyte than those of others result (⩽360nm). After crystallization, the nanotube arrays were treated with TiCl4 to enhance the photogenerated current and then integrated into the DSSC structure using a N3 ruthenium-based dye. The DSSC using TiCl4-treated TiO2 nanotube exhibited a conversion efficiency of 0.31% under 100mV/cm2 (AM 1.5) illumination. [Copyright &y& Elsevier]

Abstract: We report on the dielectric properties and leakage current characteristics of 3 mol% Mn-doped Ba0.6Sr0.4TiO3 (BST) thin films post-annealed up to 600 °C following room temperature deposition. The suitability of 3 mol% Mn-doped BST films as gate insulators for low voltage ZnO thin film transistors (TFTs) is investigated. The dielectric constant of 3 mol% Mn-doped BST films increased from 24 at in-situ deposition up to 260 at an annealing temperature of 600 °C due to increased crystallinity and the formation of perovskite phase. The measured leakage current density of 3 mol% Mn-doped BST films remained on the order of 5×10−9 to 10−8 A/cm2 without further reduction as the annealing temperature increased, thereby demonstrating significant improvement in the leakage current characteristics of in-situ grown Mn-doped BST films as compared to that (5×10−4 A/cm2 at 5 V) of pure BST films. All room temperature processed ZnO–TFTs using a 3 mol% Mn-doped BST gate insulator exhibited a field effect mobility of 1.0 cm2/Vs and low voltage device performance of less than 7 V. [Copyright &y& Elsevier]

Abstract: We reported the Ag adding effects on the crystallization behavior in Ge2Sb2Te5 film. Ag x (Ge2Sb2Te5)1− x films (where x =0–0.2) were deposited on SiO2 wafer and glass substrate by RF magnetron co-sputtering and annealed by RTA (rapid thermal annealing) at various temperature to crystallize. The effects of Ag adding on the structural, thermal and electrical properties were measured by X-ray diffraction, X-ray reflectivity, AFM, SEM, DSC and 4-point probe analysis. It was found that the crystallization temperature increased by Ag adding in Ge2Sb2Te5 films. However, the surface of Ag x (Ge2Sb2Te5)1− x films got rough when annealing temperature and Ag contents increased. According to the Kissinger method, the activation energy for crystallization increased as the Ag content increased. It is thought that Ag atoms in Ge2Sb2Te5 act as an amorphous stabilizer and they make it hard to switch from amorphous to crystalline phase. From this study, we would show the Ag0.06(Ge2Sb2Te5)0.94 film is suitable for phase change memory material because of its higher crystallization temperature and structural stability. [Copyright &y& Elsevier]

In this paper, Au/Ba0.6Sr0.4TiO3 (BST) ferroelectric thin-film interdigital capacitors on MgO substrate are presented. The interdigital capacitors with a 50-μm gap and different doped materials of BST thin film are characterized. Tunability rates of 11.2% and 28% are obtained for the undoped BST thin film and the Mn-doped (3 mol %) BST thin film, respectively, at 3.5 GHz with a bias voltage of 20 V. Furthermore, the loss tangent of the BST thin film is found to be approximately 0.0158 and it decreases with Mn doping. Mn-doped (3 mol %) BST film is suggested to be an effective candidate for high-performance tunable device applications. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 15–18, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20709 [ABSTRACT FROM AUTHOR]

LiCoO2 thin films have received attention as cathodes of thin-film microbatteries in these days. In this study, LiCoO2 thin films were fabricated by a sol–gel spin coating method and an annealing process. They were deposited on Pt(111) and Pt(200) substrates to investigate the effect of orientation of current collector. The crystallinity, microstructure and electrochemical properties of final films are also studied by XRD, SEM and galvanostatic charge/discharge cycling test. Films heat-treated under appropriate conditions exhibit high capacity and good crystallinity so those films are considered to be candidates as cathodes for thin-film microbatteries. [Copyright &y& Elsevier]

Electrochemically active lithium nickel cobalt oxide thin-film has not been fabricated until now. To fabricate stoichiometric lithium nickel cobaltate films, a sputtering target of proper composition has been synthesized via a solid-state reaction. The films are deposited by RF magnetron sputtering at room temperature. As-deposited films show an amorphous structure. By varying the deposition conditions—such as the working pressures and deposition times—thin-films with different characteristics are produced. The relationship between physical characteristics and electrochemical properties is investigated. A crystallized thin-film prepared by an annealing method displays a good discharge capacity and cycle life. [Copyright &y& Elsevier]

Close packed arrays of hollow SnO2hemispheres were prepared using PMMA microspheres as sacrificial templates for subsequent sputter-deposition of SnO2films, leading to a threefold enhancement in gas sensitivity compared to non-templated (flat) films. [ABSTRACT FROM AUTHOR]