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Descriptions of the cambial variants of the lianoids in two families, Lardizabalaceae and Sabiaceae, were lacking in Taiwan. This study aimed to diagnose the stem characteristics of seven lianoid species from these two families to update existing knowledge. Specifically, the transverse sections of fresh stems were diagnosed to generate a key. The results showed that all seven species develop one of ten cambial variant types, viz. axial vascular elements in segments. Of these species, Sabia swinhoei Hemsley, Stauntonia obovata Hemsley, and S. obovatifoliola Hayata formed secondary rays. The thick and successive periderm was apparent in Stauntonia obovata and S. obovatifoliola at older stem. The sclerenchyma ring was continuous or discontinuous in two genera (Akebia and Stauntonia), but was absent in Sabia. Four diagnostic features could be used to distinguish Lardizabalaceae and Sabiaceae; namely, the periderm, cortical sclerenchyma, vessel arrangement, and cortex ducts. The cambial variations documented for these seven lianoid species in Taiwan update existing information, facilitating comparisons between Lardizabalaceae and Sabiaceae.

We introduce a method to enhance the luminescence of GaN-based LEDs by combining the direct heteroepitaxy laterally overgrowth (DHELO) technique with selective wet etching process. The epitaxial overgrowth of GaN layers on sapphire substrate with SiO2 micro-rods array exhibited a reduced dislocation density and improved the crystal quality. The EL intensity of LEDs with SiO2 micro-rods array was 6.5% higher than conventional LEDs at 20 mA. The selective wet etching process was then used to texture the LED sidewalls into inverted pyramid shape. Finally, the EL intensity could be further enhanced about 12.5% as compared with LEDs with SiO2 micro-rods array when adopting the textured sidewalls. 2011 Published by Elsevier B.V.

Micro- and nano-scale patterned sapphire substrates (PSS) were fabricated by conventional photolithography and nanosphere lithography, respectively. Nitride-based light-emitting diodes (LEDs) were grown on different pattern sizes of patterned sapphire substrates, and the structural, electrical, optical properties of these LEDs were investigated throughout. The structural properties clearly indicate that the crystalline quality of epitaxial GaN film could be effectively improved by using the PSS technique. The leakage current is related to the crystalline quality of epitaxial GaN film, and it was also improved by using the PSS technique. The forward voltages of the LEDs grown on different pattern sizes of the PSS were similar. The light output power and external quantum efficiency of the LED grown on nano-scale of the PSS was the largest in all the samples. It indicates that the pattern size of the PSS is related to the capability of light extraction.

AlGaInP-based light-emitting diodes (LEDs) with nano-mesh ZnO layers were fabricated by using nanosphere lithography. With 20-mA injection current, the output powers of the nano-mesh ZnO, planar ZnO, and conventional LEDs (LED-I, LED-II, and LED-III, respectively) were approximately 1.66, 1.58, and 1.44 mW, respectively. The improvement of output power in LED-I could be attributed to the nano-mesh ZnO layer that acts as light scattering centers at the surface. In addition, the intermediate refractive index (about n=2) of nano-mesh ZnO layer between those of the p-GaP window layer and air results in the broader critical angle and the reduction of the total internal reflection.

High-performance nitride-based light-emitting diodes (LEDs) grown with SiO2 microrod array have been demonstrated. The light output power of LEDs with SiO2 microrod array was 9.03% higher than conventional LEDs at the injection current of 20 mA. The improvement contributed to the enhancement of the light extraction efficiency, and epitaxial GaN film quality improved by direct heteroepitaxial lateral overgrowth with SiO2 microrod array. The light output power could be further enhanced by about 18.36% as compared with the conventional LEDs when adopting the textured sidewall surface which use buffered oxide etch to remove SiO2 microrod arrays and use NaOH to etch the sidewall again into an inverted pyramid shape. After the texturing process, the LEDs show higher electroluminescence intensity and broader far-field pattern. Furthermore, the LEDs with SiO2 microrod array and additional wet-etching process will not affect the electrical property.

GaN-based light-emitting diodes (LEDs) grown on photonic crystal-patterned sapphire substrates (PCPSS) have been demonstrated. PCPSS was fabricated by nanosphere lithography, and the photonic crystal structure was the hexagonal-lattice pattern. The forward voltages of PCPSS and patterned sapphire substrates (PSS) LEDs were smaller than that of conventional sapphire substrates (CSS) LED, and it infers the epitaxial film quality of PCPSS and PSS LEDs has been slightly improved. The luminance intensity of PCPSS LED was 1.63 and 1.51 times higher than those of CSS and PSS LED at 20 mA injection current. The enhancement in the luminance intensity of PCPSS LED is attributed to the photonic crystal structure.

This paper presents the estimation of the interference of NH 3 on the detection of NO by using neural network (NN) model. The NO Rayleigh surface acoustic wave (RSAW) sensor coated with polyaniline/WO 3 (PANI/WO 3 ) nanocomposite was employed as the detection sensor. The data sensed by RSAW sensor was collected and implemented and the detection property of the RSAW sensor was studied at room temperature. A neural network RSAW identifier is expected to be created in order to estimate the interference of NH 3 on the NO detection of the RSAW sensor.

GaN-based light-emitting diodes (LEDs) with nanosphere layers were fabricated by spin-coating method. It was found that the LEDs with and without nanosphere layers had the same electrical characteristics. With 20 mA current injection, the luminance intensities of the LEDs with nanosphere layers of 300 nm and 500 nm diameters exceeded that of the LED without nanosphere layers by 5.72% and 9.05%, respectively. The improvement of the luminance intensity is attributed to the periodic structure of nanosphere layers increasing the light extraction of photons.

The nanopatterned sapphire substrates (NPSSs) with aspect ratio that varied from 2.00 to 2.50 were fabricated by nanoimprint lithography. We could improve the epitaxial film quality and enhance the light extraction efficiency by NPSS technique. In this work, the aspect ratio effects on the performances of GaN-based light-emitting diodes (LEDs) with NPSS were investigated. The light output enhancement of GaN-based LEDs with NPSS was increased from 11% to 27% as the aspect ratio of the NPSS increases from 2.00 to 2.50. Owing to the same improvement of crystalline quality by using various aspect ratios of NPSS, these results indicated that the aspect ratio of the NPSS is strongly related to the light extraction efficiency.

The wafer bonding process and chemical mechanical polishing (CMP) technique are used to remove the sapphire substrate for fabricating the thin-GaN light emitting diodes (LEDs). The stress effects in GaN epilayers on very thin sapphire substrates are analyzed by Raman spectroscopy and photoluminescence (PL). By reducing the thickness of the sapphire substrate from 450 µm to the range between 1.1 and 20.3 µm, the compressive stress in GaN epilayers will be almost released. By analyzing the main scattering signal of E2 (high) mode, the sample with thinnest sapphire of 1.1 µm exhibits 248.3 MPa stress relaxation which is obtained from the Raman shift Δω of 1.54 cm-1. By analyzing the variation of the biaxial stress with sapphire thickness, the relationship between the Raman wavenumbers ω (in cm-1) and residual sapphire thicknesses d (in µm) can be expressed by ω=569.51-1.92×exp (-d/5.81) (cm-1). Finally, an almost linear relationship between residual sapphire thickness and energy bandgap of GaN films was also observed during the CMP process.