Thermally and mechanically dependable two-dimensional (2D) photonic band gap lasers are proposed and realized at room temperature. The thin slab photonic band gap laser structure is sandwiched between air and a drilled aluminum oxide layer provided by wafer fusion techniques. In this thin slab structure, the optical confinement of photons is achieved by 2D triangular photonic lattice in horizontal plane and total internal reflection in vertical direction. Pulsed lasing action is observed at 1.54 μm by optical pumping with duty cycle up to 10%. Polarization characteristics of two-dimensional photonic band gap defect modes are also studied below and above the lasing threshold.

In this study, we have demonstrated a novel organic− inorganic hybrid gate dielectric material, zirconium tetraacrylate (ZrTA). ZrTA gate dielectric, where inorganic Zr elements are embedded in organic acrylate matrix, takes advantage of the complementary properties of single organic or inorganic gate dielectrics. A simple spin-coating and UV-assisted cross-linking reaction of acrylate moieties allowed ZrTA film to be photopatterned. The cross-linked ZrTA film by UV and heat treatments (UV, 365 nm for 3 min; heat, 120 °C for 30 min) showed high dielectric strength (10 −7 A/cm 2 at 2 MV/cm), and dielectric constant (5.48). In addition, surface properties of the ZrTA film (surface energy, surface roughness) were favorable for the growth of overlying pentacene organic semiconductor. Consequently, the organic thin-film transistor composed of a pentacene semiconductor and a cross-linked ZrTA gate dielectric displayed a moderately high field-effect mobility of 0.50 cm 2 /(V•s) with a negligible hysteresis transfer characteristic.

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The remoras are marine species that can effectively move by clinging onto other marine species via a suction disk on their dorsal side, which is composed of complex structures. The inner suction disk could be divided into three large parts, namely, lip, lamella, and spinule. The lamella is deformed actively to generate pressure difference between the inside and outside of the suction disk, and the lip maintains the sealing. The spinule, which is composed of hairs with diameter of 300 μm or less hair, enhances the frictional force. In this study, we easily fabricated polymer-based adhesive inspired by the suction disk of the remora and conducted an experiment to determine its performance. The adhesive exhibited admirable performance with a 26.68 N cm–2 (266.8 kPa) pull-off strength and a 19.42 N cm–2 (194.2 kPa) shear strength in water. The durability test result indicated that the adhesion and friction characteristics of the adhesive were well maintained even after multiple uses.

Electrohydrodynamic-jet (EHD-jet) printing provides an opportunity to directly assembled amorphous polymer chains in the printed pattern. Herein, an EHD-jet printed amorphous polymer was employed as the active layer for fabrication of organic field-effect transistors (OFETs). Under optimized conditions, the field-effect mobility (μ) of the EHD-jet printed OFETs was 5 times higher than the highest μ observed in the spin-coated OFETs, and this improvement was achieved without the use of complex surface templating or additional pre- or post-deposition processing. As the chain alignment can be affected by the surface energy of the dielectric layer in EHD-jet printed OFETs, dielectric layers with varying wettability were examined. Near-edge X-ray absorption fine structure measurements were performed to compare the amorphous chain alignment in OFET active layers prepared by EHD-jet printing and spin coating.