GaN microcavity structure with SiO2∕ZrO2 dielectric distributed Bragg reflectors was fabricated by means of transferring an InGaN∕GaN multiple quantum well (QW) structure from the (111) Si substrate onto a sapphire carrier and wet-chemical etching of the substrate. A dip in the reflectivity spectrum of the microcavity structure is observed at a wavelength of 411nm indicating the cavity resonance mode. Also, the strong influence of the cavity on the QW photoluminescence has been observed. A sharp emission spectrum, with a linewidth of 3.5nm, occurs at a wavelength of 411nm coincided with the position of the cavity resonance mode.

Surface-textured InGaN/GaN light-emitting diodes (LEDs) coated with transparent Al2O3 powder were fabricated by natural lithography combined with inductively coupled plasma etching. For surface texturing, 300 nm size Al2O3 powder is used as an etching mask by simply coating the surface using a spin-coating process. Also, the powders are left on the surface after surface texturing to further increase extraction efficiency. At 20 mA, the light output power of the textured indium tin oxide (ITO) InGaN/GaN LEDs coated with the Al2O3 powder is enhanced by ∼112% compared with the conventional nontextured ITO LED. The enhanced light output power is attributed to the improved extraction efficiency resulting from an overall decrease in the total internal reflection due to the textured surface and the Al2O3 powder coating.

Two cases of Wilms' tumor in adolescent males are presented. The clinical and radiographic findings were unusual and both presented atypical gross and microscopic features that could be correlated with the radiographic findings. Histologic examination of both tumors showed evidence of tubular and glomerular maturation, a feature usually associated with Wilms' tumors of early infancy. One of the tumors contained a large amount of cartilage and bone. The other was grossly cystic and incorporated some features of multilocular cystadenoma, a benign metanephric tumor.

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For high efficiency GaN-based light-emitting diodes (LEDs), Al 2 O 3 powder coating and surface texturing were investigated using natural lithography and dry-etching methods to improve the light-output power of the GaN-based LED. The 300-nm-size Al 2 O 3 powder is coated on the indium tin oxide (ITO) surface at various conditions using a spin-coating method. The morphologies of the ITO surface were observed using a scanning electron microscope. The Al 2 O 3 powder is left on the ITO surface after surface-texturing to increase extraction efficiency. The light output powers of the surface-textured GaN-based LEDs coated with the Al 2 O 3 powders are enhanced by 66% compared with the conventional LED at 20 mA.