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In present work, structural, morphological and optical properties of glancing angle deposited (GLAD ~ 82°) ZrO 2 thin films by RF magnetron sputtering at different substrate rotation (ω) have been investigated and compared with normally deposited (ND ~ 0°) ZrO 2 films. Both GLAD and ND ZrO 2 films exhibit preferential structural growth of monoclinic phase oriented in different directions. GLAD films also depict a tetragonal peak which has been attributed to the presence of fine nano-crystallite size (~ 13 nm). Surface correlation length of such films decreases with the increase in ω. The decrease has been attributed to the change in columnar microstructure with ω. RMS roughness values for GLAD and ND ZrO2 films are 4.6–5.1 nm and 1 nm, respectively. Dominant atomic shadowing is responsible for high roughness of GLAD films. Refractive index derived from ellipsometric measurements manifests a decreasing trend with parameter, ω. The trend has also been explained in terms of varying columnar micro-structure. Refractive index for GLAD ZrO 2 films varies from 1.901 and 2.011 on varying ω from 0.50 to 4 rpm. ND ZrO 2 film exhibits refractive index value of 2.178 which is substantially greater than that of GLAD films. Lowering in refractive index of GLAD films has been attributed to dominant atomic shadowing at glancing angles. Residual stress switches from large compressive to small tensile as the deposition angle changes from 0° to 82°. For GLAD films, tensile stress increases with the increase in ω except for the film deposited at the highest substrate rotation. Lowering in stress for GLAD films compared to ND films and trend of stress with ω have been explained in terms of varying inter-molecular forces with inter-columnar distance. [ABSTRACT FROM AUTHOR]

One dimensional photonic crystal (1DPC) of TiO 2 /SiO 2 multilayer has been fabricated by sequential asymmetric bipolar pulsed dc magnetron sputtering of TiO 2 and radio frequency magnetron sputtering of SiO 2 to achieve wide omnidirectional photonic band in the visible region. The microstructure and optical response of the TiO 2 /SiO 2 photonic crystal have been characterized by atomic force microscopy, scanning electron microscopy and spectrophotometry respectively. The surface of the photonic crystal is very smooth having surface roughness of 2.6 nm. Reflection and transmission spectra have been measured in the wavelength range 300 to 1000 nm for both transverse electric and transverse magnetic waves. Wide high reflection photonic band gap (∆ λ = 245 nm) in the visible and near infrared regions (592–837 nm) at normal incidence has been achieved. The measured photonic band gap (PBG) is found well matching with the calculated photonic band gap of an infinite 1DPC. The experimentally observed omnidirectional photonic band 592–668 nm (∆ λ = 76 nm) in the visible region with band to mid-band ratio ∆ λ/λ = 12% for reflectivity R > 99% over the incident angle range of 0°–70° is found almost matching with the calculated omnidirectional PBG. The omnidirectional reflection band is found much wider as compared to the values reported in literature so far in the visible region for TiO 2 /SiO 2 periodic photonic crystal. [ABSTRACT FROM AUTHOR]

Thin films of Ti–Zr–V alloy have been deposited using an indigenously developed DC magnetron sputtering system. The microstructure of the deposited films investigated by GIXRD, AFM and FESEM exhibited a morphology that depended on substrate and deposition environment. Films deposited on stainless steel (SS) substrates in argon ambient exhibited a columnar growth with nanocrystalline grains of about 40 nm. The films were also studied using the X-ray photo-emission electron spectroscopy (XPS) after annealing them in-situ at different temperatures for two hours in ultra-high vacuum environment. The results observed through variations in the oxidation state showed that the heat treatment in vacuum leads to disappearance of the superficial oxide layer covering the Ti–V–Zr films. After heating at 180 °C the metal-oxides changed into metallic surface that was extremely conducive to adsorption of surrounding gaseous species followed by their absorption or chemical fixation. The studies suggest that the films deposited on SS substrates are suitable as a Non-Evaporable Getter (NEG) to achieve extreme high vacuum (XHV). [ABSTRACT FROM AUTHOR]

Glancing angle deposition of HfO 2 thin films by RF magnetron sputtering technique has been explored with respect to two vital deposition parameters visualizing angle of deposition (at 82° and 86° glancing angles) and target to substrate distance, D TS in the range 70–125 mm. AFM and spectroscopic ellipsometry measurements show that at optimum D TS of 110 mm and glancing angle 82°, the films exhibit nanostructures with an estimated lowest refractive index ∼1.63 at 550 nm. For both the deposition angles, with decrease in D TS the round shaped grains of the film surface as obtained from AFM images are found to coalesce and produce films with elliptical shaped grains at shorter target to substrate distance. With increase in D TS the deposition rate first decreases up to D TS = 110 mm and subsequently increases. The phenomenon has been ascribed to the competition between reduced deposition flux density and increased sticking coefficient due to decrease in adatom kinetic energy with the increase in D TS . GIXRD measurement reveals that all the films exhibit monoclinic crystal structure. At lower D TS , the crystallinity has improved with increase in deposition angle whereas at higher D TS (>90 mm) the crystallinity becomes poorer with increase in deposition angle. The fact has been explained in light of variation of shadowing effect and deposition rate. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiO 2 thin film electrodes prepared by rf magnetron sputtering on polished SS substrates. • Lithium Ion Batteries (LIB's) have been prepared with these samples as anodes. • LIB's show high value of capacity with increasing trend with charging/discharging cycles. • Synergy between TiO 2 films and Fe 2 O 3 layers present on the SS substrates leads to high capacity. • Results very important for development of thin film based all sold-state micro-batteries. TiO 2 thin film electrodes have been prepared using radio-frequency magnetron sputtering technique on polished stainless-steel substrates. Films with amorphous, anatase and rutile phases have been obtained by varying the preparation conditions and coin cell type Lithium Ion Batteries (LIB's) have been prepared with these samples as anodes. During the cycling test, all the samples show a gradual increase in capacity with increasing no. of charging/discharging cycles after an initial decrease with the cell containing the rutile phase TiO 2 showing the highest specific capacity of around 1.217 mAh.cm-2.μm−1 after 1000 cycles at a high current density of 0.127 mA.cm−2, which is better than any reported value so far. Structural and morphological investigations of the samples by various techniques show that a synergy between the deposited TiO 2 film and the Fe 2 O 3 layers present on the SS substrate alongwith an increase in porosity in the films during the charge–discharge cycling gives rise to the remarkably high capacity of the cells which increases gradually with cycling. The present study shows that LIB's with composite TiO 2 /Fe 2 O 3 anode having advantage of structural stability of TiO 2 and better diffusion kinetics of Fe 2 O 3 can be obtained by a simple, easily scalable, reproducible rf magnetron sputtering technique and specific capacities of the present LIB's are comparable to or better than that obtained through much more complicated and multi-step chemical processes and hence the results are important for large scale technological applications. [ABSTRACT FROM AUTHOR]