Semiconductor light emitting device and method for fabricating the same

Abstract

A semiconductor light emitting device is composed of a blue light emitting diode, a red light emitting layer grown epitaxially on the blue light emitting diode, and an insulating material containing a YAG fluorescent material. The red light emitting layer is made of, e.g., undoped In 0.4 Ga 0.6 N having a forbidden band width of 1.9 eV and formed on a p-type semiconductor layer to have a configuration consisting of a plurality of mutually spaced-apart islands.

1 . A semiconductor light emitting device comprising:
 a light emitting diode comprising a plurality of semiconductor layers for emitting first emission light;   a semiconductor film provided to absorb the first emission light and emit second emission light; and   a transparent electrode provided in the light emitting diode,   wherein the semiconductor film emits the second emission light through optical excitation by the first emission light,   wherein the transparent electrode transmits the first emission light or the second emission light,   wherein the semiconductor film and the transparent electrode are located on a light emitting surface of the light emitting diode, and   and wherein the transparent electrode is provided with a plurality of openings and the semiconductor film is located in each of the openings on a light emitting surface of the light emitting diode.   
   
   
       2 . The semiconductor light emitting device of  claim 1 , further comprising:
 a fluorescent material covering the light emitting diode and the semiconductor film,   wherein the fluorescent material absorbs the first emission light and emits third emission light.   
   
   
       3 . The semiconductor light emitting device of  claim 1 , wherein the light emitting diode or the semiconductor film is formed on a substrate made of a single crystal. 
   
   
       4 . The semiconductor light emitting device of  claim 3 , wherein the substrate transmits the first emission light and the second emission light. 
   
   
       5 . The semiconductor light emitting device of  claim 3 , wherein the single crystal is sapphire, silicon carbide, gallium nitride, aluminum nitride, magnesium oxide, lithium gallium oxide, lithium aluminum oxide, lithium aluminum oxide, or a mixed crystal of lithium gallium oxide and lithium aluminum oxide. 
   
   
       6 . The semiconductor light emitting device of  claim 1 , wherein the semiconductor film is formed to cover a part of the transparent electrode in the vicinity of the openings. 
   
   
       7 . The semiconductor light emitting device of  claim 6 , wherein the semiconductor film has a crystal defect density which is lower in the portion thereof located on the transparent electrode than in each of the portions thereof located over the individual openings of the transparent electrode. 
   
   
       8 . The semiconductor light emitting device of  claim 1 , wherein the first emission light is blue light or ultraviolet light. 
   
   
       9 . The semiconductor light emitting device of  claim 8 , wherein the semiconductor film is excited by the first emission light to emit the second emission light which is red light. 
   
   
       10 . The semiconductor light emitting device of  claim 1 , wherein the semiconductor film is composed of a plurality of semiconductor films which are stacked in layers and emit emission light components having different wavelengths from each of the stacked layers. 
   
   
       11 . The semiconductor light emitting device of  claim 1 , further comprising a metal film in a portion of the electrode and having a thickness of at least 10 μm, wherein a current is injected in the light emitting diode through the metal film. 
   
   
       12 . The semiconductor light emitting device of  claim 11 , wherein the metal film is made of gold, copper, or silver. 
   
   
       13 . The semiconductor light emitting device of  claim 1 , wherein the light emitting diode is provided with a metal electrode having a reflectivity of 60% or more with respect to the first emission light or the second emission light. 
   
   
       14 . The semiconductor light emitting device of  claim 13 , wherein the metal electrode is composed of a single-layer film or a multi-layer film each made of at least one material selected from the group consisting of gold, platinum, copper, silver, and rhodium.