[en] We fabricated very thin solid silver films with thicknesses below 50 nm using a spin coating method. An aqueous silver ionic complex solution was spin-coated and then thermally cured for a few minutes at a low temperature. The properties of the spin-coated silver films were compared to the properties of silver films deposited by thermal evaporation. The spin-coated thin silver films possessed silver crystallinity and a surface roughness of ∼ 2.83 nm, while the thermally evaporated thin silver films also possessed silver crystallinity with a surface roughness of ∼ 2.44 nm. Long-range surface plasmon polariton (LR-SPP) waveguides fabricated by both spin coating and thermal evaporation were also characterized and compared. The propagation losses of the 23 nm thick spin-coated and the 19 nm thick evaporated LR-SPP waveguides with strip widths of 7 μm were 3.6 and 4.2 dB/cm, respectively, and their coupling losses were 1.4 and 1.0 dB/2facets, respectively. The use of the spin coating method is a very cost effective solution because the films can be formed at low temperature in a short period of time without requiring a vacuum system. In addition, there are many potential applications of using spin-coated very thin solid silver films in LR-SPP waveguides and nano electrical circuit patterns.

[en] 3.6 nm sized Mn-doped Zn_1-xCd_xS quantum dots (QDs) with the composition (x) of 1, 0.5, 0.2 and 0 were synthesized by a reverse micelle approach. The bandgap energy of Zn_1-xCd_xS:Mn QDs was tuned to a higher energy by increasing the Zn content, and the actual composition of alloyed Zn_1-xCd_xS:Mn QDs was found to be different from the solution composition. Consecutive overcoating of the Zn_1-xCd_xS:Mn QD surface by a ZnS shell was done, and the core/shell structured QDs exhibited quantum yields of 14-30%, depending on the composition of the core QDs. Using CdS:Mn/ZnS QDs, orange and white light-emitting diodes (LEDs) pumped by a near-UV and blue LED chips, respectively, were fabricated and their optical properties are described.

[en] The effect of photo irradiation on the refractive index of spirobenzopyran (SP) polymer was investigated. Spirobenzopyran polymers were prepared by a radical polymerization using 6-(p-methacryloyloxy-hexyloxyphenyl)carbonylspirobenzopyran, styrene, and butylmethacrylate. Films with spirobenzopyran polymers showed color change from pale yellow to deep blue upon irradiation of a monochromatic light of 340 nm, The colored films were bleached either spontaneously or by light of 580 nm. The refractive index changes of the spirobenzopyran polymers were 5x10^-4 and 9x10^-4 for 20 wt% and 35 wt% of the spirobenzopyran content, respectively

[en] Highlights: • Competitive adsorption of Br^‒ vs. bis(3-sulfopropyl) disulfide (SPS) was explored. • Br^‒ formed a strong suppression layer with polyethylene glycol (PEG). • Br^‒ effectively interrupted the adsorption of SPS under strong convection. • The concentration ratio of Br^‒ and SPS is critical for Cu bottom-up filling. -- Abstract: A three–additive combination of an accelerator, a polymeric suppressor, and an organic leveler is typically utilized in the electrodeposition process to achieve Cu bottom–up filling of microvias on printed circuit boards. The use of several organic chemicals makes maintaining the performance of the electrolyte and additives more complicated due to the decomposition of the organic additives. As a replacement for the organic levelers, inorganic levelers, such as bromide ions, can avoid this problem since halide ions cannot produce organic by–products. This study investigates the effects of bromide ions on the adsorption of polymeric suppressors and accelerators and the influence of the concentration ratio of bromide ions and the accelerator on the bottom–up filling of microvias. The electrochemical analyses reveal that the bromide ions are adsorbed on the Cu surface and interact with the polymeric suppressor, increasing the suppression effect. In addition, bromide ions combined with the polymeric suppressor retard adsorption of the accelerator, and forced convection enhances the inhibitory effect of bromide ions. Electrochemical analyses also suggest that the accelerator to bromide ion concentration ratio is critical for controlling the surface activity for Cu electrodeposition and dictates the bottom–up filling characteristics. Microvia filling experiments indicate that in the optimum concentration ratio range (i.e., 0.2 < [SPS]/[Br^‒] < 0.7), Cu electrodeposition starts at the bottom corners of the microvias and is effectively inhibited outside the microvias, leading to successful Cu bottom–up filling at the microvias.

[en] We investigated the damp heat stability of Ga-doped ZnO (GZO) thin films grown on glass substrates. GZO thin films with thicknesses of 150 nm were grown on glass substrates by rf-magnetron sputtering. After the deposition, a damp heat stability test was performed at various temperature (50 ∼ 65 .deg. C) and relative humidities (80 ∼ 90%) for up to 240 hr. With increasing temperature and humidity, the sheet resistance of the GZO thin films increased to a maximum of 14.2% at 65 .deg. C/90% RH. The changes of surface morphology caused by damp heat were drastic and were comparable to the degradation caused by high temperature only. The effect of damp heat is discussed based on the electrical and the structural characterizations.

[en] Al (1at.%)-doped ZnO (AZO) nanofibers with diameters of 257-627nm were prepared by using electrospun PVA/zinc acetate-aluminum chloride composite fibers by drying for 24h at 80deg. C in vacuum and subsequent annealing for 2h at temperatures in the range of 400deg. C to 600deg. C in air. The properties of AZO fibers were characterized with an aid of XRD, DSC/TG, FT-IR, SEM, TEM, spectrofluorometer, viscometer, pycnometer and dynamic tensiometer. Uniform and smooth fibers with a diameter of 257nm were observed for the AZO fibers containing polyvinyl alcohol of 40g at a flow rate of 0.05ml/h and an electric field of 1.1kV/cm. The FT-IR observation of the strong and broad absorption peaks of O-H bonds around 3430cm^-1 and 2361cm^-1 suggested that the interstitial H atoms were bonded with oxygen atoms for the O-H stretch modes. The peaks around ∼ 1635cm^-1 may be responsible for the Zn-H bond, a zinc vacancy having two hydrogen atoms. Photoluminescence spectra at room temperature showed a narrow ultraviolet emission at 3.24eV and a broad green emission at 2.43eV. A peak broadening in the green emission may be attributed to Al doping

[en] Highlights: ► Highly conductive and transparent AZO composition was explored by CCS method. ► The optimized composition was 3.13 wt.% Al doped ZnO deposited at room temperature. ► Resistivity was 6.5 × 10⁻⁴ Ω cm and average transmittance was 92% in visible region. ► In the damp heat test, the sheet resistance does not change even after 1000 h. -- Abstract: Al doped ZnO (AZO) thin films were deposited at room temperature by continuous composition spread method. Various compositions of AZO thin films deposited at room temperature were explored to find excellent electrical and optical properties. The explored composition, 3.13 wt.% Al doped ZnO, was obtained with the lowest resistivity and the highest transmittance. We deposited the optimized AZO composition by on-axis RF sputtering to deposit uniform large area thin film and got a thin film with superior electrical, optical, and damp heat properties although it deposited at room temperature (resistivity: 6.5 × 10⁻⁴ Ω cm, average transmittance in visible region: 92%)