| 摘要 |
A light-emitting device includes: a semiconductor structure (220) formed on one side of a substrate (215), the semiconductor structure (220) having a plurality of semiconductor layers and an active region (225) within the layers; and first and second conductive electrodes (232,238) contacting respectively different semiconductor layers of the structure; the substrate comprising a material having a refractive index n > 2.0 and light absorption coefficient alpha , at the emission wavelength of the active region, of alpha < 3 cm<-1>. In a preferred embodiment, the substrate material has a refractive index n > 2.3, and the light absorption coefficient, alpha , of the substrate material is alpha < 1 cm<-1>. <IMAGE> |
