Enhanced light output power of thin film GaN-based high voltage light-emitting diodes.

The characteristics of high-voltage light-emitting diodes (HVLEDs) consisting of a 64-cell LED array were investigated by employing various LED structures. Two types of HVLED were examined: a standard HVLED with a single roughened indium tin oxide (ITO) surface grown on a sapphire substrate and a thin-film HVLED (TF-HVLED) with a roughened n-GaN and ITO double side transferred to a mirror/silicon substrate. At an injection current of 24 mA, the output powers of the HVLEDs fabricated using a sapphire substrate and those fabricated using a mirror/silicon substrate were 170 and 216 mW, respectively.

Self-textured oxide structure for improved performance of 365 nm ultraviolet vertical-type light-emitting diodes.

High performance 365 nm vertical-type ultraviolet light-emitting diodes (LEDs) are demonstrated by the insertion of a self-textured oxide mask (STOM) structure using metal-organic chemical vapor deposition. The dislocation densities were reduced significantly via the STOM by the observation of the transmission electron microcopy image. Under an injection current of 20 mA, a 50% light output power enhancement was achieved, representing an enhancement of 35.

AFM membrane roughness as a probe to identify oxidative stress-induced cellular apoptosis.

The morphological change of cellular apoptosis initiates from the change of membrane roughness. In order to identify cellular apoptosis in its early stage, atomic force microscope was adapted to reveal the change of membrane roughness in unprecedented details, providing an image in nanometer-scaled resolution. The mouse monocyte/macrophage cell line RAW 264.