Optical device

Abstract

An optical device is provided. Multi-layer structures are disposed on a substrate, wherein each of the multi-layer structures is consisting of at least two insulated layers with different refractive indexes formed alternately. A buffer layer covers the multi-layer structures, so that said multi-layer structures are disposed between the buffer layer and the substrate, wherein said buffer layer is an un-doped GaN based semiconductor layer. A first conductive semiconductor layer is disposed on the buffer layer. An active layer is disposed on said first conductive semiconductor layer. A second conductive semiconductor layer is disposed on said active layer and a transparent conductive layer is disposed on said second conductive semiconductor layer.

What is claimed is: 
     
         1 . An optical device, comprising:
 a substrate;   a plurality of multi-layer structures disposed on said substrate, wherein each of said multi-layer structures is consisting of at least two insulated layers with different refractive indexes formed alternately;   a buffer layer covering said multi-layer structures, so that said multi-layer structures are disposed between the buffer layer and the substrate, wherein said buffer layer is an un-doped GaN based semiconductor layer;   a first conductive semiconductor layer disposed on the buffer layer;   an active layer disposed on said first conductive semiconductor layer;   a second conductive semiconductor layer disposed on said active layer; and   a transparent conductive layer disposed on said second conductive semiconductor layer.   
     
     
         2 . The optical device of  claim 1 , wherein each of said multi-layer structures includes a first insulated layer and a second insulated layer formed on said first insulated layer, and said first insulated layer's refractive index is larger than said second insulated layer's refractive index. 
     
     
         3 . The optical device of  claim 1 , wherein each of said multi-layer structures includes a first insulated layer and a second insulated layer formed on said first insulated layer, and said first insulated layer's refractive index is smaller than said second insulated layer's refractive index. 
     
     
         4 . The optical device of  claim 1 , wherein said optical device further comprises a first electrode formed on a bottom surface of said substrate which is relative away from the multi-layer structures. 
     
     
         5 . The optical device of  claim 1 , wherein said optical device further comprises a first electrode formed on a surface portion of said first conductive semiconductor layer. 
     
     
         6 . The optical device of  claim 1 , wherein said transparent conductive layer exposes a portion of a surface of said second conductive semiconductor layer. 
     
     
         7 . The optical device of  claim 6 , wherein said optical device further includes a second electrode formed on said exposed surface of said second conductive semiconductor layer and contacting with said transparent conductive layer. 
     
     
         8 . The optical device of  claim 1 , wherein said optical device further includes a second electrode formed on said transparent conductive layer, and said transparent conductive layer is disposed between the second electrode and said second conductive semiconductor layer. 
     
     
         9 . The optical device of  claim 1 , wherein said multi-layer structure is selected from the group consisting of: SiO x , Si x N y , SiO x N y , ZnSe, TiO 2 , and Ta 2 O 2 . 
     
     
         10 . The optical device of  claim 1 , wherein each of the multi-layer structures having a thickness of ½ wave length is used to be as an anti-reflective layer. 
     
     
         11 . The optical device of  claim 1 , wherein a bottom of each of the multi-layer structures abuts on the substrate. 
     
     
         12 . An optical device, comprising:
 a substrate;   a plurality of multi-layer structures disposed on said substrate, and each of said multi-layer structures consisted of at least two insulated layers with different refractive indexes formed alternately and having a thickness of ½ wave length, so as to be used as a anti-reflective layer;   a first conductive semiconductor layer disposed on said substrate to cover said multi-layer structures;   an active layer disposed on said first conductive semiconductor layer;   a second conductive semiconductor layer disposed on said active layer; and   a transparent conductive layer disposed on said second conductive semiconductor layer.