Deep-seated tectonic tremors have been regarded as an observation tied to interconnected fluids at depth, which have been well documented in worldwide subduction zones and transform faults but not in a collisional mountain belt. In this study we explore the general features of collisional tremors in Taiwan and discuss the possible generation mechanism. In the 4 year data, we find 231 ambient tremor episodes with durations ranging from 5 to 30 min. In addition to a coseismic slip-induced stress change from nearby major earthquake, increased tremor rate is also highly correlated with the active, normal faulting earthquake swarms at the shallower depth. Both the tremor and earthquake swarm activities are confined in a small, area where the high attenuation, high thermal anomaly, the boundary between high and low resistivity, and localized veins on the surfaces distributed, suggesting the involvement of fluids from metamorphic dehydration within the orogen.

The KrF pulsed excimer laser (248nm) and the frequency-tripled neodymium doped yttrium aluminum garnet laser (355nm) have been used to separate GaN thin films from sapphire substrates and transfer to bond other substrate. However, these processes would increase the dislocation density, resulting in an increase of the leakage current. In this study, the effects of these two laser sources on the reverse-bias leakages of InGaN-GaN light-emitting diodes were studied. (c) 2007 American Institute of Physics

The InGaN-GaN epitaxial films were grown by low-pressure metal-organic chemical vapor deposition on a sapphire substrate, and then the light-emitting diode ͑LED͒ with double roughened ͑p-GaN and undoped-GaN͒ surfaces was fabricated by surface-roughening, wafer-bonding, and laser lift-off technologies. It was found that the front side luminance intensity of double roughened LED was 2.77 times higher than that of the conventional LED at an injection current of 20 mA. The backside luminance intensity was 2.37 times higher than that of the conventional LED. This is because the double roughened surfaces can provide photons multiple chances to escape from the LED surface, and redirect photons, which were originally emitted out of the escape cone, back into the escape cone.

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An InGaN–GaN light-emitting diode (LED) with a roughened undoped-GaN surface and a silver mirror on the sapphire substrate was fabricated through a double transfer method. It was found that, at an injection current of 20mA, its luminance intensity was 100% larger than conventional LEDs. Its output power was 49% larger than conventional LEDs.

The frequency-tripled neodymium-doped yttrium aluminum garnet laser ͑355 nm͒ and the KrF pulsed excimer laser ͑248 nm͒ were employed to separate GaN thin films from sapphire substrates and to transfer the films to bond with other substrates. The different laser lift-off processes would generate the dislocation density on different regions. In this study, the effects of these two laser sources on structural damage mechanisms and reverse-bias leakages of InGaN-GaN light-emitting diodes ͑LEDs͒ were studied.

Gallium nitride is considered a chemically inert, ceramic-like semiconductor with no effective etchants available at room temperature. In this letter, we study the shape transformation of nanoporous GaN prepared by an electrochemical process. It is found that the curvature-driven mass transport process at typical growth temperatures is effective in shaping GaN on both the nanoscale and microscale into useful configurations such as buried cavities or semiconductor-on-air structures. This process of “micromachining” GaN adds flexibilities to epitaxy and device designs. A monocrystalline GaN nanomembrane, extending millimeters in width, is reported as a proof-of-concept demonstration.