Internal absorption loss in GaN layers was investigated for GaN-based Schottky-type light-emitting diodes (ST-LEDs) operating in the UV spectral region. The peak energy of electroluminescence (EL) spectra of the device observed from its substrate side was shifted towards energy lower than those observed from its surface side. This is due to the internal absorption loss in the GaN layer. In particular, the large excitonic absorption in the GaN layer is one of the obstacles for light extraction from the ST-LEDs. Thus, light extraction from the surface side is effective for reduction of the internal absorption loss. (c) 2008 Elsevier B.V. All rights reserved.